EPT. 22 , 1893.]

BRiflSH COLONIES AT CHICAGO. III. - NEW SOUTH w .ALE .•

THE most important contribution to the \Vorld's Columbia.n Expo~ition made by the British Empire, and n0t exclud1ng the Mother Country, is un­doubtedly that of the colony of New South \Vales. In every department of the Exhibition it is prominent, and in some p re-eminent, amonv foreign exhibitors. In mining, in forestry, i~ agriculture, in viticulture, in the liberal arts, and in ethnology, the exhibits of New South \Vales eclipse those of England, and will constitute a lasting monument to the richness of the country and the energy of the people. Even in other departments where the colony might well have been expected to have little worth showing, she has made a good display ; in transportation and in fisheries, manu­factures, machinery, transportation, and in woman's work, the contributions of New South \Vales are more than creditable. Over two thousand exhi­bitors have contributed to this resul t, and neither time, money, nor skill have been spared to bring New South \Vales into this conspicuous place among the nations exhibiting . The colony has been exceptionally fortunate in securing the Hon. Arthur Renwick as Executive Commissioner, this gentleman not only having displayed remark­able energy and ability in the performance of his onerous duties, but he has known how to make himself highly esteemed and popular in the Exhibi­tion and in Chicago.

It will be quite impossible within the limits of a single article to do justice to the exhibit of New South Wales, but we hope as the result of a careful examination, and with the aid of the admirable catalogues (by far the best and n1ost comple te in the Exhibition), to give our readers some idea of the importance and extent of the section, which, of course, has been organised and administered inde­pendently of this country.

We will take first the magnificent display in the Mines and Mining Building, from which a good idea of the mineral wealth of the colony ma.y be obtained. In the general classification of the Exhibition, the exhibits of mines and mining are assigned to Depart­ment E, and occupy Groups 4.2 to 68, comprising Classes 290 to 412. The New South Wales exhibits are limited to Groups 42 to 48, although the objects shown might, had it been considered desirable, have been distributed amongst most of the others. The Classes 290 and 291, collections of minerals syste­Inatically arranged, and collections of ores and the associated minerals, and diamonds and gems rough, uncut, and unmounted, respectively, comprise about 200 exhibitors, most of whom send a large number of objects. Naturally gold and gold ores take the lead in this remarkable collection. Long before it was known in later times that Australia was an auriferous country, the Portuguese, those wonder­ful pioneers in the early days of geographical dis­covery, had learned the alluring fact, and on a sixteenth-century map had marked the north­western shores of the southern continent as the " Gold Coast." In recent times the date when gold was discovered was February 23, 1823, when a Government engineer engaged on a survey of the Fish River found particles of gold in the sand hills near the stream. In 1839 auriferous pyrites were found near Wellington, and in 1841 gold was dis­covered in the granite formation ; this discovery was made by the Rev. vV. B. Clarke, and for him Sir Archibald Geikie claims the credit of being t.he first scientific explorer who announced the existence of auriferous veins in Australia. Between that time and a few years later, when the search for gold drew thousands of adventurers from all parts of the world to Australia, the precious metal in one form or another was frequently recognised in various parts of the colony. Geological formations with w bich gold is uRually associated are known to exist over an area of 70,000 square miles, nearly one-fourth the extent of the colony, so that, vast as has been the amount of precious metals extracted- up to the end of last year at least lOt millions of ounces had been obtained- there is reason to suppose that the average production of the past will be main­tained for many years to come. Gold is found in quartz x:eefs and a.lluvial deposits, t he former intersecting the sedimentary rocks of the Upper Silurian, Devonian, and Carboniferous periods, as well as in granites, porphyry, diorite basalt, and serpentine; the latter belong to the Permian, Cretaceous, Tertiary, and Quatenary ages. The reefs vary in thickness from a few inches to 10 ft..

E N G I N E E R I N G. Alluvial gold is usually found in flat flakes or scales, much waterworn. The older deposits, always the result of denudation and erosion, are in many cases covered by more recent volcanic deposits, in some instances 200 ft . thick , and these have to be drilled t o reach the auriferous gravel. The most recen t deposits are found in the water-courses running through alluvial flats, and many of these are very rich. \Vater is the agency generally employed for separating this g0ld, but in many places water in sufficient quantities does not exist, and methods of dry Eeparation by air blasts have been tried with success. The reef gold is usually accompanied with sulphurets, such as pyrites, galena, copper, &c . The presence of arsenic, antimony, iron, and other metallic combinations, adds to the difficulty and cost of reducing t he gold ores. By the Department of Mines and Agncul­ture, the auriferous regions of New South Wales are divided into twelve districts and forty-two divisions. Of these, the districts of Peel and Uralla (classified together), Bathurst, and Lachlan gave the largest yields in 1892, having been about 32,000 oz., 15,000 oz., and 8000 oz. respectively. It is curious to note the great difference in the yields from the same mining division in successive years. Thus, in 1891, from the Bathurst division, Bathurst dis trict, were produced 3370 oz. , and last year only 805 oz.; from the Orange division of the same district, the yield was 1678 oz. in 1891, and 12,708 oz. in 1892. In the N undle division of the Peel and lfralla district 1023 oz. were found in 1891, and 22 oz. last year. The total result of last year's working- 144,999 oz.--showed a decrease on t hat of 1891 of 18,Q96 oz. The exhibits relating to this class of natural wealth consist principally of specimens of ore, though there is a large and interesting collection of alluvial gold and of nuggets. Five of these latter are famous specimens ; they are the "~Iaitland Bar, " containing 313.093 oz. of fine gold ; one containing 258.33 oz. ; another of 41. 53 oz. ; a fourth of nearly 43 oz. ; and a fifth of 14.85 oz. All these are shown by the Department of Mines and Agriculture, and in addition this deparbnent contributes no less than 217 specimens of gold-bearing quartz, granite, or other rock from different mines in the colony, the whole illustrating admirably the varied conditions under which the metal exists. In addition the department shows 47 examples of alluvial gold from different fields, ranging in value from 8520 parts of fine gold in 10,000 to 9825 parts per 10,000; in all cases silver is associated in minute quantities. The remainder of the gold exhibit is made up by the contribu­tions from fifteen companies, varying from picked samples of rich quartz to masses of the poorest rock that can be treated with profit. Probably the most attractive specimen is a block from the Chambigue Company's mine near Grafton, assaying 17 oz. to the ton.

Silver mining in New South Wales is of more recent date than that of gold, it having been com­menced in 1879. In a few years the industry assumed very large dimensions, and to the end of 1892, ore of the value of 13,779, OOOl. had been extracted. Of all the silver mines in the colony that of Broken Hill is the best known and most successful. It is situated on the summit of a ridge that rises about 150 ft. above the surrounding level : the crest is formed by the outcropping lode, varying in width from 10 ft. to 120 ft. Mr. C. S. Wilkinson, the late Government geologist, says of this formation : ''It is a true fissure lode, consisting chiefly of porous iron and manganese oxides, in places more or less silicious, containing carbonates of lead and chlorides of silver, with occasionally carbonates of copper and zinc. The lode continues northerly with much the same character, narrowing and widening in places, and beyond it seems to continue in irregular smaller lodes of a more silicious character, containing argentiferous galena and carbonates of lead and copper, with a little chloride of silver." No less than 3,896,000l. have been paid in dividends from this mine, out of which 803,497 tons of ore have been taken, containing 30,757,505 oz. of silver and 125,102 tons of lead. During last year prolonged strikes interfered with the progress of the works, and it would seem as if the depreciated value of silver would permanently and injuriously affect its prosperity. Numerous other silver mines exist in the colony, most of them con­taining ore largely associated with lead, ~nd in some cases with paying gold ; altogether, thuteen com­panies are represented in the Mining Building at J ackson Park by exhibits. Of these the Broken

3SI

Hill is t he largest conttibutor. The Binghi silver mine in theN ew England district sends eamples of ore bearing the following analy sio :

Silver ... ... .. , ... 28 oz. 17 dwt. 2 gr. per ton.

Lead .. . . . . .. . . . . 14.93 per cent. Antimony ... ... ... 11.24 ,

The Broken Hill Company Eends carbonate, sulphide, and silver lead ores, together with many interesting particulars of its operations. From these we learn that the Australian shareholders have received 5l . 3s. 4d. in dividends on each Ss. share since 1886. The smelting plant consists of fifteen 60in. by 112in. water-jacketed furnaces, the normal charge of each of wh1ch is 49! tons per twenty­four hours. A large leaching plant has been com­pleted during the last eighteen months, and in this during 34 weeks' work 14,800 tons of concentratrd tailings were treated, yielding 71,738 oz. of silver, at a cost of 6s. 1d. per ton of tailings. During the twelve months ending May, 1892, there were t reated :

Tons. L ead ore . .. .. . ... ... ... 126,692 Silicious iron ore and kaolin .. . .. . 116,742 Iron ore .. . .. . .. . .. . .. . 3, 473

The fuel and fiuxes used in dealing with these amounts were :

Tons. Coke... ... ... ... ... ... 44,452 Coal ... ... .. . .. . . .. ... 7,057 Limestone . .. .. . .. . . . .. . 79,241 Ironstone ... .. . .. . .. . .. . 7, 750

As with the gold exhibit, the Minister for Mines and Agriculture makes a very tine display of silver ores and specimens, there being no fewer than 300 different examples. These include lead ores, the two metals being so closely combined that they are classified together. The tin deposits of New South Wales were not worked till about 1870; up to the end of 1892 this metal has added 9,840,000l. to the wealth of the colony. Well­defined lodes of tin are numerous, but the metal is almost wholly obtained from alluvial deposits either on the surface, in the beds of existing creeks, or in old river bottoms covered by subsequent de­posits ; the approximate area of the tinfields is nearly 5! million acres. The Minister of Mines and Agriculture shows nearly 200 specimens of stream tin and lode tin ore, and there are besides a few other exhibitors.

Copper to the extent of 6,211,000l. had been mined in New South Wales to the end of 1892; the cupriferous area is nearly 7000 square miles, and there are five principal lodes containing carbonates, metallic copper, and sulphides. The Minister for Mines and Agriculture is again the chief exhibitor, practically the only one except for 5 tons of yellow sulphide ore from the Cobar mine, which, by the way, has lately been closed on account of the low prevailing prices. Antimony is found over a wide area, commonly combined with gold, but generally inseparable from it, on account of metallurgical difficulties in treatment ; there is pos­sibly a future for mining this metal in New South Wales, but up to the present time the output has been only about 120,000l. The Mine Department shows eighty-three specimens of auriferous antimony ore, stibnite and cervantite, from almost as many dif­ferent mines. A laboratory collection of metals very rare- so far as known- in the colony, such as bismuth and molybdenum found in tin-bearing drifts, wolfram, zinc, and platinum, the latter occurring occasionally in gold-bearing gravels, is shown by the Mines Department, but is without commercial interest. It is otherwise with iron, chromium, and cobalt. So far as iron is concerned, the time has not yet come for it to be largely ob­tained from the ore in the colony, but in many localities it exists abundantly, as magnetite, brown hematite, limonite, and bug ores ; in one district the quantity in sight is estimated at nearly 3 million tons of about 48 per cent. metallic iron. There is a large number of exhibitors of iron chromium and cobalt ores.

Precious stones, though neither very numerous nor varied, must be ranked among the sources of wealth to the colony. About 50,000 diamonds have been found up to the present time ; probably the specimens shown in the gem collection of the Minister of Mines represent some of the largest stones yet discovered; the heaviest is 7! carate. Besides the diamond, the following gems are found, and are well represented in the Mines Building : the sapphire, emerald, ruby. opal, amethyst, gar­net, topaz. A large deposit of emeralds has recently

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SEPT. 22, 1893·] E N G I N E E R I N G. 353

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been discovered, and 25,000 carats were obtained during 1892 ; the hardness of the matrix rendered it difficult to obtain the gems without fracturing them. Opals of high quality are not infrequent in thin veins existing in the sandstones on the River Darling ; stones to the value of 15, OOOl. were found in 1890. \Ve have no room in the present article to do justice to the noble display of coal made by New South Wales in her allotment in the Mines Building ; but before concluding for the present, we must say a word about the splendid collection of fossils from the principal sedimentary formations of New South Wales, prepared by the State geolo­gist, and sent by the Minister of Mines and Agri­culture; they comprise 472 specimens. These, with three or four private collections of minerals obtained from all par ts of the colony, complete the collection in Classes 290 and 291, in which, as we have already said, nearly all the exhibits of New South Wales (excepting fuel) are placed.

(To be continued. )

THE TOWER BRIDGE. IN a former issue* we gave some illustrations of

the work being done on the Tower Bridge, showing the state of completion at that date- viz., eptember last. At that time we stated that we should on a later occasion give fuller details of this important struct ure ; that promise we now fulfil. As will be seen by the general view- Fig. 1, on the opposite page- the bridge consists of three spans- viz. , two approaches on the suspension principle, and a cen­tral lifting bridge. Subsidiary to the latter, there are two foot-bridges, at a sufficient height to allow for the masts of vessels requiring to proceed to the wharves above to pass underneath. The middle span is 200ft. in the clear, while~ thos~ on ~ither side are 270 ft. each. The operung br1dge 1s on the bascule system, each leaf extending 100 ft. The leaves will be actuated by hydraulic machinery, placed in suitable chambers in the piers. The

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centre of the pivot is 13 ft . 3 in. inside the face of the pier, so that the total length of each movable part from the centre of the pivot to the end is 113 ft. 3 in. The short end of the lifting part is 49 ft. 3 in. This is loaded at the end with kent ­ledge to balance the longer arm, which projects over the waterway when the bridge is closed. Although the towers forming the principal features in the bridge a pp ear to be of masonry­and indeed are masonry so far as appear­ance goes-the main structure is steel ; that is to say, there is a steel skeleton, clothed with stone­work. This method of construction adds not only to the expense, but to the weight to be borne by the foundations ; it has, however, been adopted in order that the bridge may harmonise with the Tower of London. We think the designers may be con­gratulated on the general success they have achieved in this respect, considering the task set before them was one of such difficulty. A modern bridge conveys such different impressions to a medi~val structure like the Tower of London, that the task must have appeared almost hopeless. It was naturally impossible to cover the steelwork of the spans themselves, but after all a lifting bridge is of the essence of medirevalism, the drawbridges of ancient castles being the prototype. Putting aside these msthetic considerations, however, we will proceed to our description of the engineering details of the bridge.

The main piers will contain hydraulic machinery for operating the bascule, and the footways above will be approached by means of hydraulic lifts in t he towers themselves. The length of each of the fixed spans forming the footways is 237 ft., and each consists of two cantilevers and a centre girder. The height of the columns of the towers is 119ft. 3 in. There are three landings to each tower, the floors being of steel. The approaches to the piers, as already stated, are on the suspension principle, but the chains are of novel design, being formed of two segments of unequal lengths.

The Tower Bridge iR being constructed by the

Corporation of London. The original proposal for a bascule opening bridge was made by the City Architect , the late Sir Horace J ones, with whom was associated Mr. J. W olfe Barry, who is now engineer to the undertaking. The Bridge H ouse Estates Committee has the direction of the matter ; Mr. A. Purssell being the chairman of that body and Mr. A. M. Nortier the secretary. Mr. G. E. W. Cruttwell is resident engineer. The contractors for the steelwork are Messrs. Sir William Arrol and Co. ; Mr. J. E. Tuit being engineer-in-charge. The contractor for the foundations was Mr. J ohn Jackson, who was represented on the works by Messrs. W. Wilkinson and G. H. Scott. Messrs. P erry and Co. are contractors for the masonry, and Messrs. ~Hr William Armstrong, Mitchell, and Co. are supplying the hydraulic machinery. Mr. J ohn J ackson was also contractor for the Middlesex abutment, and Mr. John W ebster for the Surrey abutment.

In our description it will be appropriate that we should deal with the foundations first, and we are able to do this with more completeness, owing to the fact that Mr. Cruttwell has recently contributed a paper on the foundations of this bridge to the Institution of Civil Engineers, from which paper we take several of the following particulars. As Mr. Cruttwell points out, the weight of the opening roadway, added to that of the high-level footway, and the towers supporting them, renders the load upon the foundations unusually heavy for a bridge of such moderate span. The foundations are carried down to the London clay, which forms the bottom of the bed of the river at this part, with a slight layer of gravel or river mud above it . As it was determined to limit the load to the very moderate amount of 4 tons per superficial foot, the dimensions of the foundations work out to 100ft. in width, and 2041 ft. from end to end of the cutwaters. The necessity for so large an area of foundation has been questioned, but Mr. Barry had had previous experience of a somewhat similar kind. One of his earliest works, he stated in the discuesion on

354 E N G I N E E R I N G. [SEPT. 2 2, I 8gJ. ~~~~~~==~====~~~~~~~~~~~~======~~~~~-­Mr. Cruttwell's paper, was connected with the pier is not shown built in, but this was finished, as superficial feet to the supporting area of th~ Charing Cross Bridge, where the total pressure on shown in Figs. 6, 8, and 9. The additional briok- pier. the L ondon clay was about 7 tons per square foot. work shown in the latter illustrations had to bond The excavation being performed, concrete was At Cannon-street Bridge it was considerably re- with that in Fig. 3, and therefore the inner side of filled in in the usual way, the timber frames being duced, being 4t to 5 tons per square foot; yet in each of the permanent caissons had to be cut away. removed as the work proceeded, and, where neces­both these bridges subsidence has occurred, and As stated, the permanent caissons are those below sary, raking struts being applied. The top 2ft. though not serious it is perceptible. It may be water. The principal dimensions of the work are inside the caisson is of brickwork, but before corn­stated, however, that before the size of the founda- marked on the drawings, so that it is not necessary mencing the building above the level of the per­~ion~ was finally determined, a trial cylinder, 6 ft. to repeat them. The permanent caissons were manent caissons they had to be supported by struts 1n dtameter, was sunk on the site of the bridgo, supplied by Messrs. Head, "\Vrightson, and Co., (Fig. 10) at each timber frame. These were to and experiments were carried out with it. The and the temporary caissons by Messrs. Bow and take t he place of diagonals which had afterwards result was that after the weight of 6i tons per McLachlan. . t o be withdrawn. This being done, piles were s9.uare foot had been reached, the clay began to In sinking, the caissons were kept level by a driven (as already mentioned) in the 2ft. 6 in. yteld, and ihe settlement kept on increasing. It suspending gear from the staging, attachment being space between the caissons, so as to form a water­was, therefore, considered that 6} tons was the made to each corner. A space of 2 ft. 6 in. was tight joint. These piles were only driven at the tnaximum load that could be supported, and, as Mr. left between each of the different caissons, as shown ends of the spaces, i.e., near the corners of the Cruttwell points out, considering that the slightest in the illustration. These spaces were filled up by caissons, and a spac~ was therefore left inclosed on unequal settlement of the bridge with all its driving piles between. In this way a. complete t he two longer sides by the caisson, and at the ends n1achinery, where the parts have to fit so accurately, cofferdam was mad~. The caissons above the bed by the piles. This space was next pumped out, would have been disastrous, it was decided to limit of the river were removed when the masonry was and the sides of the temporary caissons, or t he the load to 4 tons. Sir Benjamin Baker has said built up to the level of 116ft. 6 in., or 4ft. above part above the river bed, could be removed. The that he does not know of any other bridge founda- high water. In Fjgs. 4 to 9 the details of the above applies to the caissons at the central parts of tions with such dimensions as those of the Tower piers are shown . They are built of gault brick in the piers; the sides of the caissons next to the end Bridge, except in the case of the Brooklyn Bridge, cement mortar of 2! to 1, and are faced with Cor- caissons had, however, to remain until later, and which has nearly the same area. of foundation. nish granite. Each pier contains two stccumulator neithAr of the sides of the end caisson could be re­The two main foundations in the American bridge chambers, a bascule chamber, and two machinery moved until the walls had been built up, as shown support a roadway of 1606 ft. span, or about the chambers. The bascule chamber, a cross-section in Fig. 10. In building the latter, the strutP, same as that of the Tower Bridge. In r egard to of which is shown in Fig. 9, is a rece~s, into which shown by dotted lines on the drawings, had to be obstruction to the waterway-a charge which has the short arm of the lifting bridge sinks. It goes inserted at each frame of timber as soon as the occasionally been brought against the new bridge- to 9 ft. of the bed of the river. The chief parti- building had been brought up to the underside of Mr. Walmisley has given some interesting figures: culars are again given on the drawings, but it may the frame. These struts had to take the place of 70 ft. for the pier he said was not excessive under be repeated here that the finished dimensions of the struts which were withdrawn after the building the circumstances; old London Bridge, with nine- each pier are 70 ft. wide by 154 ft. 8 in. long from had set sufficiently to withstand the pressure from teen arches, had two-thirds of waterway occupied point to point at a central line at t he water level. the struts shown by the dotted lines. It was then by piers. Old Westminster Bridge had one-third, At foundations they are each 204ft. 6 in. from toe possible to carry the masonry and brickwork up to and Vauxhall Bridge has one-sixth. As in the to toe by 100 ft. wide. the underside of the frame next above, and the Tower Bridge there are twice 140ft. out of 740 ft. The piers were constructed in the following same process was repeated until the wall was built available, between one-fifth and one-sixth of the manner : The permanent caissons were riveted up to a height of 4ft. above Trinity high water; as river width is taken up by piers in the new together on platforms betwuen the stages above the work was brought up water was let into the structure. Another advantage in the Tower low-water level, and beams were laid across. From lower parts of the temporary caisson, so as to relieve Bridge is that the piers are few in number, these beams-indicated at Fig. 10 by dot-and-dash the pressure against the newly-built wall. and it is not so much that a number of narrow lines-the caissons were suspended by four 2!-in. The next operation was to excavate and build waterways are required, as two or three of good lowering rods, the latter being tested to 22 tons. between the caissons, the work already described width. In the Tower Bridge the 200ft. space is in By means of screws at the upper ends of the being that which was required within the caissons. the centre, where it is most required, in deep water. lowering rJds each caisson was lifted clear of the As soon as the sides of the temporary caissons had It may also b e pointed out that in t he Pool vessels platform, which was then removed ; and by revers- been removed, as previously stated, the space are ranged in tiers and occupy a large part of the ing the screws the caisson was lowered to the between the caissons was excavated down to 10ft. waterway. As a mattar of fact, the two piers of the bottom of the river. In order to insert additional below the tops of the permanent caissons. The 'fower Bridge take up less space than the moored lengths of the lowering rods whilst lowering, the space was then filled with concrete up to within vessels, so that therd is more room where the bridge weight of the caisson was taken by other rods 2ft. of the top of the permanent caisson, and 2ft. occurs for the pas~age of craft, than immediately attached by hooks passing underneath the cutting of brickwork were put on the top of this. The higher up or lower down. edgas of the caisson. The last-mentioned roda wall was then built continuously up to 4 ft. above

In sinking the foundations there was more than were removed when the bottom of the river was Trinity high water. Struts were inserted at each ordinary difficulty in one respect, owing to the great reached. The caisson being in place, the excavation frame of timber before the struts crossing the traffic of the P ool. The conditions imposed by the could be commenced by a grab working in the caissons were removed. This operation was carried river authorities were that 160 ft. clear was to be middle of the caisson, and by divers shovelling out in a manner similar to that described for the kept in the fairway for the passage of craft. As from around the cutting edge. The latter was struts in the end caissons. The wall having been the finished waterway between the piers is 200 ft., composed of a special rolled steel of 25 lb. to built within the end caissons as described, the piles there was but small room for the temporary works the foot run. The water jet was used, and the were driven and the sides of the temporary caissons required for sinking the piers, and in consequence frames were loaded up with kentledge. When the were removed. The timber being withdrawn, the con­of this it was found necessary t o sink first one pier cutting edge had penetrated through the ballast tinuous wall round the whole pier was built. Before, and then the other. The method of procedure is and well into t he clay, the water was pumped however, the central portion of the pier was entirely shown in Fig. 2, which is a general plan of the out, and the work proceeded in the dry. The inclosed, a 12-in. iron pipP, furnished with a sluice work of the piers and abutments. Here the limit minimum depth which the caisson was required to valve, was laid so as to connect the central part of of the firdt stage of the works is shown by cross- have been sunk into the clay before pumping was the pier with the river. As soon as the wall was hatching. The arrangement is also shown in allowed was 4ft. In order to guide the descent of built completely round the pier, t he inside piles Fig. 3, which is a longitudinal section. By refer- the caissons the lowering rods were kept in position were able to be taken out, and the backs of all the ence to these illustrations it will be seen that the until the caisson had been sunk to its full depth. temporary caissons removed and transferred to the piles were driven ~nd the te~porary ~ork go~ into For t he purpose of the undercutting which was re- second pier. The struts were then placed across position for the M1ddlesex pier. This occupted a quired, shoes were provided to put under the the central portion of the pier at intervals of about width of 135 ft. In the Surrey pier there would bottom. The advantages of this undercutting have 5 ft. vertically down to low-water level. It was be 22 ft. 6 in. short of the required waterway been questioned, and Sir Benjamin Baker has then possible to pump out the central part, and between if the works had been built out in like pointed out that though the scheme gives a larger the excavation proceeded in the dry. As previously manner.' The Middlesex pier was finished up to area of clay for the foundations to rest upon, its stated, the backs of the permanent caissons were the point necessary, an~ the piling removed .. The advantages are not so great as might appear at first removed by cutting the rivets connecting them to full width was then avallable for the Surrey pter. sight, as the projecting toe probably diminishes the the sides, but the sides and fronts of the permanent

In sinking the foundations for piers, eight r~ct- efficiency of the side friction. Mr. Shelford has caissons remained. The struts were, of course, angular iron c~issons . were u~ed for e~ch pier, pointed out that there would be a considerable removed as the building was brought up to them. timber cofferdams being speCially forbidden by tensile strain in the base of the concrete at the heel In order to bond together the various parts of the Act of Parliament. These caissons were 28ft. of the toe, and that the settlement of such a bridge concrete foundations, boxes were built in, and on square, and were arranged in th~ position s~own in on the clay tended to take the form of a curved these being removed the spaces left formed the the drawing; there were also !n each p1er four line, and the pressure therefore must be very dovetail into which the concrete of the next portion caissons of an approximately tr~an~ular .s~ape, as severe upon the toe, and this would tend to crack constructed would be filled. The steel and iron shown. These caissons were bmlt m pos1t10n, and if not to sheer the concrete. Mr. Barry questioned skeleton, or framework, which practically consti­are mainly permanent below the river bed, into this theory, and is unable to see that the toe would tutes the bridge itself (the encasing masonry being which they extend 19ft., so as t o reach the London come into tension unless it was presumed that the almost entirely for ornamental purposes), will next 1 large mass of concrete and brickwork, which was, occupy our attention.

c the clay was undercut below the cuttin_g edge of as it were, a beam extending ov~r the whole surface, The illustrations on page 352 are a plan and eleva­the caisson when the latter had reached Its lowest could be held to bend. The strength of the struc- tion of the general arrangement of the iron and steel p osition f~r a vertical distance of 7 ft., and 5 ft. ture a.s a beam was so enormous that it was futile work. The central bridge,as before stated, consists of outward' from the face of the caisson. This gave a to suppose there could be any such bending. The two fixed and one opening span; the two fixed spans depth of foundation of 26 ft. below the bed of the substructure, therefore, rested upon the clay as one formingthehigh-levelfootway. Thedistancebetween river. These foundations are of ceme~t concrete homogeneous body, and what~ver added to the the two piers is a little over 230ft., and the height

6 t 1 pt the top 2 ft. which IS of gault area would add to the supportmg strength. The in the clear, above Trinity high water, is 140ft. bri~kw~rk~ce In Fig. 3 t he ce~tral portion ot the I undercutting, it may be mentioned, adds 3800 This limits the height of vessels pasaing under at

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SEPT. 22, 1893·]

high water; it is, however, sufficient for the pur­pose, for the Tower Bridge is but a short distance f~o~ London Bridge, whic.h ~efines the navigable hmtt of the Thames for sh1pp1ng proper-that is vessels with masts t hat will not lower. The water~ way between the piers is 200 ft. wide.

(To be continued.)

THE BRITISH ASSOCIATION. THE sixty-third annual meeting of the British

Association for the Advancement of Science has just been held at Nottingham under the presidency o~ Dr . . J: S. Burd~n Sa?derson, P rofessor of :Phy­swlogy 1n the Un1vers1ty of Oxford, having com­menced 01~ the 13th inst., an~ c.oncluded yesterday, the 21st ln9t. The AssoClatlon authorities un­doubt.ed ly hav~ exercised their discretion wisely in selectmg N ott1ngham for the 1893 meeting. A member remarked at one of the meetings, that '' nobody goes to Nottingham unless obliged, '' by which the maladroit member did not mean that Nottingham was a place to be avoided, but that it is not a stopping place, or stepping-stone, for other important districts. However that may be, very few of the members now assembled-at the time of writing- appear to have been in Nottingham before, and now they are here they ~eem excel­lently well pleased. It is not, however, the Associat ion's first meeting in ''The Queen of the Midlands " - as the Nottingham folk delight to style their city- for twenty-seven years ago there was a. gathering here under the presidency of Mr. Grove ; who has since t urned his scientific know­ledge to good account on the bench. N otting­ham has the great advantage of being pic­turesque. I t stands on a hilly site, and in its ancient streets are many relics of domest ic medireval architecture which yet survive the ravages of modern improvement. Those, how­ever, who remember the meeting of 186G, will miss many of the most treasured ' ' bits. " The old Bridlesmith's Gate has recently been '' improved ' ' from a picturesque old-world corner to a modern highway, and other q uaintly pleasant spots have been brought more in accordance with the age of cleanliness, convenience, and monotony. Still a good deal remains, and t he historic market-place, the boast of Nottingham through all the Midlands, is as crowded with booths as ever it could have been in the days when R obin H ood, Alan-a-Dale, and Much, the miller'a son, came in from Sherwood to chuck the delighted maidens of the market under the chin, or spend the broad pieces of despoiled churchmen in the neighbouring taverns. In one respect, however, the most devoted lover of the past will find no fault with the march of improve­ment. When the Association last visited the city, Nottingham Castle was but a shell of bare walls ; gaunt and stark as left by the reform rioters of 1831. N ow it is a comfortable museum, owned by the corporat ion; the two great social functions of the meeting were appropriately held in its ample galleries.

F or excursions - without which the .Association meetings would be as dry bones to so many of the members and associates-Nottingham is an espe­cially good centre. There is still a Sherwood F orest ; the Dukeries are well within reach ; South­well, with i ta sylvan cathedral, is but a short run ; whilst D onnington, Haddon, Buxton, and .Burleigh were all visited on the Saturday. For the longer whole-day excursions of Thursday a very attractive programme was prepared, including a more ex­tended visit to the Dukeries, Chatsworth and Haddon, Charnwood Forest, Dovedale, Castleton, and Matlock. F or the more ut ilitarian, trips had been arranged to the Midland Rail way Works, to the N ottingham Gas 'N orks, and to W ollaton Colliery, but the latter excursion was knocked on the head by the strikes.

Of the evening entertainments we may say a few words here. The President's address was given on the first Wednesday evening as usual. Dr. Burdon Sanderson is a biologist, and his inaugural discourse does not come at all within our province. On Thursday, the 14th, t he Mayor of Nottingham gave a soiree in the castle. On Friday, the 15th, Professor A. Smith ells lectured at the Al bert H all on ''Flame. " On Monday last Professor V. H orsley discoursed on '' The Discovery of the Physiology of the Nervous System ;" and on Tuesday last there was another soiree at the castle. Professor Vivian B . Lewes gave the usual lecture

E N G I N E E R I N G.

to working men on "Spontaneous Combustion" on the Saturday evening.

Having. so far dealt with the general aspect of the meetmg, we may pass to the more detailed notice of proceedings in the sections more espe­cialJy within our sphere.

MECHANICA-L ScrENOE. Section G is the one which more nearly concerns

our readers,. and . we . will com~ence our report of the meetmg w1th 1ts proceedmgs. The P resi­dent this year is Mr. J eremiah Head, who read his inaugural address on the morning of Thursday the 14th inst. '

THE P RESIDENT's ADDREss. It is not often that a large audience assembles in

Section G t o hear the presidential address, as mechanical science has little attraction for t hose who are not engineers. Mr. H ead, however , struck out a new line, and those who happened to be present were qui te able to follow the interest­ing facts put forward . On another page we deal with Mr. Head's address, and need not, therefor e, make furt her reference to it here.

B ALANCI NG R ECIPROCATING MoTION. The first paper down for reading in Section G

was a contribution by Mr. ,V. W. Beaumont, and dealt with an arrangement of "Automatic Balance of Reciprocating Mechanism " which the author had devised. F or the purpose of illustrating the inven­tion, the author exhibited a number of working models made to represent sieves, screens, &c . We shall return to this subj ect at a future date, as without the aid of illustrations it would be difficult to describe the method of working, but it may be said that Mr. Beaumont showed that his device quite fulfilled the promise he made for it, and there is no doubt but that the discovery is one of considerable interest. In his paper th e author pointed out that in most cases of vibration of machi­nery, whether of rotary or reciprocating forms, the vibration is due to the rebtriction of the motion which would naturally occur if the nominally sta­tionary parts were free to act under the infi uence of the disturbing force. Rotating parts can generally be balanced with success, but in many cases it cannot be achieved with reciprocating parts. The more ordinary method of balancing improves the working of machinery, but involves framing of greatstrength, and mechanism with large bearings and great accu­racy of fitting, and does not materially reduce the vibration set up in buildings containing machinery. The object of the author 's invention is t o avoid these undesirable results, whilst at the same time the strerJgth, cost, and power may be all reduced by completely reversing the usual proceeding, and actually utilising the source of vibration for work­ing the reciprocating machinery. The operating parts are therefore purposely put out of balance, and are attached to the moving parts, instead of being attached to fi xed parts. In this way the unbalanced motor parts are automatically balanced by setting up as much motion in the thing to be moved as is necessary to absorb the momentum of the unbalanced part throughout its path. All vibration of the supporting part is thus avoided.

The discussion on this paper was opened by Professor Unwin, who said the device introduced by Mr. Beaumont was quite new, and an exceedingly useful bit of mechanism, which would have many practical applications. The author had spoken of the difficulty of balancing reciprocating and ro­t,ating motions. The speaker pointed out that there was no difficulty if both motions were separately provided for, but the trouble arose when an effort was made to balance a reciprocating motion by a rotating weight ; in Melbourne an instance had been brought before him, where it was intended to balance a locomotive by excep­tionally heavy weights, with a result that the engine tore up 3 mil~s of line. Mr. U~win ~ad seen a short t ime prevwusly a steam turbine wh1eh made 25,000 revolutions per minute. In tha~ case everything possible had to be done to get rid of the forces due to want of balance. With a turbine they could get a balance one way by means of knife edges, but that was not altogether satisfactory. In the case referred to, a long and thin spindle was used by means of which the axis of the weight and the axis of rotation were made to coincide when the machine was running at high speed, so that the motion was vPry steady, notwithstanding t~at there was coneiderable vibration whilst the turb1ne was getting up speed.

355 Mr. Gisbert Kapp pointed out that t he paper

had two aspects, namely, that in which the me· chanism was made to produce motion, and that in which it was designed to prevent motion. Mr. Beaumont had conveyed power to a riddle by means of a flexible thin wire, but the speaker would be glad to know if the wire would be sufficiently flexible and, at the same time, suflicient1y strong, if the sieve were loaded. He had listened to the paper with very grea-t interesb, for he had often been under the necessity of scheming some means of getting rid of the vibration to which dynamos were subject when running at the high speed necessary for their efficient working. It was useless to balance the armature on knife edges, because excess of weight on opposite sides would balance each other axially, but not transversely. In order to properly balance any rotating body the want of balance must be found out whilst the body is rotating. For this purpose the speaker had made a frame with suspended bearings into which the armature was placed, and the spindle connected by a flexible shaft to an electro-motor. The bearings would then be free t o move, and the point to be balanced at either end of the armature could be found in the usual way. In foundations for electrical machinery there was no rule to guide the engineer. With the greatest care it was not always possible to avoid vibrations, the problem being of too complex a nature to be worked out. Under these circumstances, could not Mr. Beaumont's principle be applied to foundations so that they might be made elastic ? That seemed to him the only way to get over the difficulty and arrive at any certainty. Mr. Lewis said that he had introduced the author 's device to the notice of colliery managers, and the result was that it was to be applied to pit frames.

Sir B. Baker hoped Mr. Beaumont would follow up his investigations upon this most important subject. Almost wherever there was an electric installation there was vibrat ion, and the law courts were constantly occupied with lit igation arising out of the fact. It was a very difficult problem to attack on the old lines, the variations in running being quite unaccountable. On different days, and even different hours, there would be quite different results in this most important respect. The machinery would apparently be running under exactly similar conditions, the only variation that could be discovered being in the amount of vibra­tion. It had been suggested that variations in the condit ions of subsoil water caused the change. It was doubtless known to many that a good deal of attention was being given to the matter on board the Teutonic, and there the results were very diffi­cult to unravel. Diagrams had been taken, and sometimes the vibration was found to be longi­tudinal, and sometimes athwartships. The problem was an extremely difficult one, and he hoped the author would follow up his research.

Professor Rele-Shaw asked if the author could explain how the principle could be applied to an ordinary steam engine so as to lessen t he vibration. H e had shown very clearly how it could be used with a sieve, but the conditions of running an engine were very different.

Mr. A. Rigg said the discussion had largely gone away from the author's paper to the balancing of dynamcs and steam engines. Mr. Kapp, in his illustration of the dynamo, had shown a couple, which naturally produced vibration. Mr. Yarrow had gone very thoroughly into lhe vibration of the steam engine, and the meeting could hardly expect the author to go into that matter at pr~sent, although his device contained what might be the germ of a solution.

Mr. Lupton asked if colliery owners were open t o use the device.

Mr. Beaumont, in reply, said that several sub­jects had been been broached, but there were so many other papers on the agenda that he could not venture to occupy the time of the meeting by treat­ing upon all of them. Mr. Kapp asked if the riddle when loaded could be driven Ly a wire suffi­ciently flexible. That he would answer in the affirmative. The illustration of Mr. J{app showed how there may be a want of complete balance in a machine that had been tested on knife edges. His remarks t ended to support the necessity of allowing the thing to be rotat~d to go. where .it pleased, but this required w?rk1ng out 1n deta1l. The engine foundation queshon was a corollary of that which he had treated upon; and he would gladly follow up the suggestion of Sir Benjamin

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ELECTRIC LIGHTING PLANT AT THE IMPERIAL ~IEDICAL ACADEMY, ST. PETERSBURG.

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Baker as to following up the experiments and mak- 1 feature of local interest of the Nottingham meet- fashioned stocking machine had beEn in existence stocking machine led to the making of the warp ing them known to the section at a subsequent I ing. The first was a contribution by Mr. E. about 200 years, the lace machine, in fact, growing machine, but a net was wanted like t hat made by meeting. Doughty on lace machinery, and was largely of out of the stocking machine. The absence of hand on the Continent, and called Brussels net.

historical interest. The author commenced by machine tools and labour-saving appliances checked 1 After many trials by inventors, Heathcote sue-LACE AND KNITTING M ACH INERY. saying that the beginning of lace-making by machi- l progress for many years, although some improve- ceeded in making the exact net itself. Heathcote

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SEPT. 2 2, I 893·] E N G I N E E R I N G. 357

ELECTRIC LIGHTING ENGINE: IMPERIAL MEDICAL ACADEMY, ST. PETERSBURG. CON~ TRUCTED BY MR. F. SCHICHAU, ELBING, GERMANY.

dreds of machine owners, but many efforts were made to evade his patents. Leavers originated a different machine1 which, after many alterations, has come down to our time as the most useful lace machine we have. Another machine was developed out of the plain net machine for making lace curtains.

Mr. C. R . 'Vood ward next read a paper on knitting machinery. After referring to early forms of knitting machinery, the author showed by lan­tern illustrations-unfortunately imperfectly seen, owing to the impossibility of excluding light from the room-the vast strides recently made, the loop­forming capacity having advanced from 500 to

(For Descnption, see Page 373.)

Fig. 2.

500,000 loops per minute ; whilst the scope of the trade embraces not only all forms of knitted under­wear, but also stockingette cloth, astrachans, Cardigan jackets, Tam-o' -Shanter caps, down to bags- " shirts " we believe they are called by the meat dealers-in which to import foreign mutton. The new era in making stockings is a return to domestic machinery, which must appear to those unconnected with the trade as a retrograde step, but it is accounted for by cheapness, the low rate of wages for which country people will work, the fact that the goods require so little finishing that "manufacturers " (the quotation marks are ours) have no factory expenses, and that much more

comfortable socks and stockings are produced on these machines than on earlier types. American machines have been largely introduced, on which one girl will knit from fifty to eighty dozen pairs of half-hose per week, but these are plain, not ribbed, fabrics. The author indicated his views of probable lines of future development as follows : Machinery which will work either by foot pedals or steam power, and in which the narrowing, widening, changing of ribs, and furming of heels, toes, &c., will be manipulated by hand in a similar manner to that in which a typewriter is worked.

At the conclusion of the reading of these two papers the section adjourned to another room in

the University College-Section G meeting in the lecture-hall of the college--where a number of machines were shown in work. These were ex­plained by Professor W. R obinson, of Nottingham.

The proceedings then closed for the day.

Friday, the 15th inst., was a busy day in Section G, there being no less than eight items on the pro­gramme.

DRYNESS OF STE .. \.M. The first business taken was the "Report of the

Committee on Dryness of Steam in Boiler Trials;" but this was merely a formal proceeding. Professor U n win stated that very little progress had been made, and the committee was, in fact, not in a posi­tion to make a report. They could only ask to be reappointed, and they hoped during the ensuing year to make substantial progress. Some investi­gations had been made on this subject in America, nnd it was thought that by working on the same lines valuable results would be obtained.

GRAPlliC METHODS.

Professor H. S. Hele-Shaw, of Liverpool, next read the ''Report of the Committee on Graphic Methods." This committee has been formed for some time, and in our account of a previous meet­ing of the Association we dealt with the second report. Although the subject is not likely to attract popular attention, it. is one of very consider­able impor tance, as going to the root of so much science teaching and exposition. The committee have expended an enormous amount of labour on the preparation of the rep01 t, which, as a m onu­ment of good and conscientious work, does credit to all concerned, but, perhaps, especially to the secretary, on whom the chief burden of the labour has naturally devolved. It is a constant source of regret to us that we have to treat good and valuable work in so brief a manner, but the limita­tions of space are absolute, and we can often do little more than indicate the scope of a monograph, referring our readers to the original for fuller in­formation. That will have to be our course in the present instance, but we will quote some of the committee's conclusions from this , the last report. There appears to be no reason why an element.ary course of a general nature, specially arranged so as to include all that an ordinary engineering student requires to know of graphical methods, should not be introduced as a regular subject in engineering schools, and the following arguments are brought forward by the committee in support of this view :

"1. Although the time-tables of an engineering department may be already full, yet it will be found that a course, such as that suggested, really includes much of what is taught at present in a desultory way. Such a course would obviate some of the teaching given under the heading of 'descriptive geometry, ' so tha.t during one or two terms of a year it might be taken during the houra already devoted to descriptive geometry, with possibly one lecture a week for one term, given in place of the actual lectures in applied engineering ; into which, at present, graphic methods are often obliged to be introduced for the want of proper preliminary training in the subject by a student. M oreover, the time now devoted in the engineering laboratory for the plotting of curves might be much better occupied in the drawing hall itself, in con ­nection with the practice of the plotting and inter­polation of curves as a part of the subject of graphic methods, the data obtained from the engineering laboratory affording useful information.

'' 2. The time spent in such graphical work would be an excellent discipline for a student in accurate drawing. A sketch, roughly repre­sentina an idea, is often regarded as sufficient for pr;"'ctical purpo~es. . A stud~nt shou~d learn for himself that nothmg Is so eas1ly deceived as the eye. Jt is quite true, as Professor Culmann says in the preface of his work, that the ~ con~tructing engineer will give preference to geometrical solu­tions wherever an accuracy of results up to three decimals (one-thousandth), which can perfectly well be obtained is sufficient, for his drawing instru­men ts are 'always at hand, and drawing is his habitual expression of thought.' But suc.h ac?~racy in drawing is by no means natur~lly or ~n~u1t1yely acquired, and the student reqUires tra1ntng 1n a course of graph ical methods before he would ~ppr~­oia.te their value. Moreover, such practiCe 1n actually performing the operations, and becoming familiar with the solution, is absolutely necessary, if it is to be expected that a student will really use

E N G I N E E R I N G.

these problems afterwards in his pract ical work, as suc_h modifications become extremely puzzling, owing to the want of a thorough acquaintance with the methods.

"3. It is not only necesssary that a student should be familiar with accurate drawing, but also that he should be familiar with graphical construc­tions as a means of solving problems. The plan ordinarily adopted in the teaching of statics, in conjunction with graphical methods themselves, seems expecting too much for the capacity of an ordinary student. In t he use of ordinary geometry or analytical methods there are separate classes for algebra, analytical geometry, trigonometry, &c., and yet the ideas involved in them are not more difficult than those included in graphical construc­tions and methods. Graphical methods certainly, therefore, have the same claim to be considered as a separate branch of study. "

The following proposition, supported by these arguments, was therefore brought forward in the report : '' That in all engineering schools a sepa­rate course in graphical methods of construction may, with advantage, be introduced, which shall deal with such problems as have a practical bear­ing on mechanical science, and which do not in­volve applications of any concrete subjects. such as statics and dynamics, but which may familiarise t he student, by means of examples accurately worked out by himself, with methods which he will be afterwards able to apply."

I t is satisfactory to know that this proposition, which was brought forward at the recent Inter­national Congress at Chicago by Professor Hele­Shaw, received the general approval of a very re­presentative body of engineers and professors.

The report concludes with a tabulated statement of the present state of the teaching of graphic methods in Europe and America.

THERMAL STORAGE AND DISPOSAL OF REFU~E.

Two papers, partly of a sanitary nature, were next read. The first was by Mr. C. C. K eep, in which the author dealt with "Thermal StortJge by Utili­sation of Towns' Refuse." The chief point in this paper was the explanation of Mr. Druitt Halpin's method of thermal storage by means of tanks con­taining water to be heated by steam generated in separate boilers. We have already described Mr. Halpin's interesting scheme, which the author looks on as indispensable to any system of burning refuse with a view to utilising the heat so obtained for electric light purposes. The author showed by means of diagrams the advantages of a stored supply of heat for power purposes, which is analogous to the gasholders now used by the gas companies so as to enable production to be constantly carried on at a uniform rate in spite of the fluctuations in demand for light.

'Ve propose returning to this paper at a future date.

The next paper was a contribution by Mr. Wm. Warn er, entitled " Disposal of Refuse. " The subject is one of ever-present interest, but it is especially of importance in view of the pos­sibility - which may yet be greater than the most sanguine will allow - of a visitation of cholera t o our shores. H owever, without cholera, there are annually thousands of lives sacrificed, and 1nillions who suffer from impaired health, by reason of our still far from perfect sanitary arrange­ments.

We may remark at this juncture that i t is much to be regretted that there should have been so strong a flavour of commercialism introduced into the section when dealing with some questions. F or instance, in a paper contributed we find figures given showing the rate at which various forms of a certain apparatus have ''gone forward " of late ; that is to say, the success that various firms have had in pushing their own particular goods. The fault lies with the section authorities, who appear far too guileless in their dispositions. A ~cientific society should be careful to exclude anything bearing so close a semblance t o advertising matter from its proceed ings. We do not blame manufacturers or inventors who are authors of papers. They naturally think their own wares the best and that they are doing notable service in help'ing forward such unrivall~d productions. Neither are we among those punsts who hold up their hands in holy horror because the reader of a paper has an axe of his own to grind in preparing a contribution which represents, probably, a large amount of valuable labour and no trifling pecuniary

[SEPT. 2 2, I 893-

outlay. 'Ve are q uite aware that if devotion to science had to be d epended upon as the sole actu­ating cause, the t echnical societies might just as well-and, indeed, would of necessity- shut up shop. The labourer is worthy of his hire ; but of no more, and the selection committee of Section G sometimes allow authors to draw rather too freely upon the wages fund.

There is much good matter in the two papers unde r notice, and we commence publishing an abstract of Mr. Warner's contribution this week. If they could have been judiciously filed down, and then welded into one, they would have formed an unexceptionable addition to the records of the Association. We commend it to the attention of Sections B, D, and G whether they could not arrange a joint committee for inquiring into this most important question of 1·efuse disposal. 'Ve can think of no more beneficial action that the Association could take ; and possessing, as it does, these three sections, it is peculiarly suited to per­form this great service to the State.

The discussion which followed turned largely on the thermal storage question, upon which Professor Unwin brought forward some facts wor th putting on record. He said that we must take it as a fact that much refuse must be burnt, and therefore a quan­tity of heat would be generated, no matter whether it were got cheaply or otherwise. I t was not, there­fore, a question whether steam could be generated for municipal purposes at less cost by burning refuse than by b urning coal, but whether it would pay to utilise the heat thus produced at all. Assuming it would be desirable not to let it go to waste, it was evident that some system of heat storage would be necessary. The heat used could only be the difference in temperature of the gases going into the boiler and the temperature of them when they come out. F or t hat reason the de­structor which burnt refuse at a high temperature would be desirable. Loss by radiation was the objection to the storage scheme, but to meet this a sys tem of insulation could be easily applied. It seemed to be a common opinion that electric light was the one great purpose for which heat from refuse- burnjng was to be applied, but the speaker questioned whether power distribution was not a better application for the electric current that could be generated. There was an increasing demand for power, and a good system of distribu­tion would be a serviceable thing.

Mr. G. Watson, of L eeds, made some useful remarks on the subject, in the course of which he commented on the various types of destructor mentioned. H e said that the question of the evaporati ve power of town refuse was one of much importance, yet he did not think that in the whole range of engineering science, there was a subject in a mor e chaotic state. Endeavours had been made to ascertain the power available by mixing up small quantities of refuse and testing them in a calori­meter ; but such a method was evidently useless, seeing that t own refuse actually contained large tins, buckets, and sacks in considerable quantities. Interesting figures had been given referring to the manufacture of manure, and it had also been stated that llb. of steam was raised by 1 lb. of refuse. This figure was probably true for the refuse in ques­tion, bu t would not always apply.

Mr. H alpin also gave particulars of his system of heat storage by hot-water tanks, illustrating the acr,ion by means of a diagram.

(To bP continued.)

GISHOLT'S T URRET LATHE. THE Gisholt Machine Company 's 3-in. standard stud

machine shown in Fig~. 1 t o 8, on page 364, is one of a number exhibited by the above company at the Columbian Exposit ion. They make a speciality of this claes of tool, of which they turn out large numbers from their works at Madison, \Vis.

The machine in question is designed for rapidly, economically, and conveniently fin ishing large screws, studs, collars, pinions, &c. , from the rough bar. It is provided with handy devices for varying the cutting speed, rate of feed , and the cutting power, as aleo with arrangemE-nts for rapidly chucking the work and bringing up the fresh pieces. The turret is made hexagonal, and is bored accurately for six tools. The turret tool post shown will carry four tools. Con­sequently ten tools can be set up at once for use on a piece of work without changing tools. Figs. 2and 3 show a longitudinal section through the headstock, and also a transverse section through the spindle. The hollow spindle is journalled in bearings which are split and tapered on the ou tside; and by means of lock nuts,

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concentric adj ustment is secured . The cone pulley is mounted loosely on the spindle, as is also the driving face gear. T~e operation of putting on the back gear can be d?ne mstantane?usly, and without stopping the machmery. To th1s end the back gear is con­struc ted so that it is always in gear with both the belt co~e and ~ith a spurwheel running loose on the sptndle. E1ther the cone or this wheel can be made solid wit h the spindle by means of the friction clutches shown in Fig. 2. These clutches are at opposite ends of a sliding colla.r which is keyed, by four keys , to a steel collar firmly fi xed to the lathe spindle. The chuck is automatic in its a ction, and its details will b e understood by referring to Fig. 3. Its d istinguish­ing feature is that i t is opened and closed by power· the hand lever being merely used t o actuate the chuck jaws. This chuck is of the class where collets are made for each size of stock to be held. Only a small movement of the collet is required to close the chuck. Firmly .fixed .to the spindle are the spur gears a and b connectmg w1th wheels c and d, which run loose on the hollow shaft shown above. Between these wheels is a rotating clutch which may be engaged, by means of the hand lever shown, to either of the gears. Con ­nected to the hollow shaft is also a third spurwheel e which engages with the toothed nut of the clutch : This nut screws on the end of the spindle, and also screws on the collar against which t he collets abut, right and left threads being employed. A key serves t o prevent rotation of the sliding member of the chuck relatively to the spindle. The wbeel a is providEd with a. brger number of tee th than b ,; and c has a. smaller number of t eeth than cl. Consequently, when gear c is clutched to the shaft, the forward motion of this shaft is faster tha.n that of the spindle ; conseq ut ntly the chuck jaws will be opened. The reverse takes place when the ch~1ck is closed. As soon as the collet tightens on the stock, the clutch slips, and herein is the chief advantage of the chuck, aside from the fact that it is very easily operated. The chuck is wholly self-adjusting a s to size, and holds stock of varying size with equal firmness.

A rapid change of feed is provided, which is illus­trated in Fig. 4; 1f is the lead screw on which the wormwheel shown is keyed. A bronze worm engages with the wormwheel. The shaft on which this worm is mounted is deeply splined and carries loose wheels. These wheels are provided with three internal key­seats, each adapted to receive the end of the feather s hown.

B etween each pair of wheels is a steel collar which serves to depress the end of the feather, and prevents it from being connected with two wheels at once. The loose wheels engage with others mounted on the shaft shown, which is driv·en by a train of gearing from the spindle, and is also provided with a. reversing motion by means of beYel gears. On t he front s ide of the lathe is a splined rod, by means of which the adjustment of the feed can be varied by the operator without leaving his p osition at the turret or carriage of the lathe.

Fig. 5 represents a top view of the turret. A block slides in a groove planed in the top of the bed, and ma y be set at any point for the purpose of auto­matically rotating the turret. A shaft geared to rotate with the t urret, ca rries six stop screws. These stop screws engage with the stop, which may be fixed at any point on the bed, and serves as an independent adjustment for each tool. This stop-bar automatically disengages the feed motion, and also serves as an in­dependent dead stop.

The carriage is shown in F ig. 6. The most im ­portant feature of this carriage is the turret tool p ost, and the automatic independent stop motion. The turret tool post is arranged to carry four tools in the grooves milled in i ts periphery, and is arranged to have independent vertical adjustment for each tool, which adjustment is made after the tool is clamped in position. The turret is provide~ with independent adjus table cross ~top screws, wh1ch are. arranged . to come in contact wtth the stop bar. It w11l be read1ly seen that a varying independent cross-slide adjust­ment for each of the four tools is readily obtained by m eans of these screwa.

The vertical a.dj ustment is obtained by means of the screws which rest on the steel registering block. The turre t tool post on the la rge machines is elevated by means of a. handwheel. The carriage is provided with a. s top motion, as shown in Fig. 7 '· for automatically disengaging the feed a t any des1red point for each tool. This stop motion is precisely the same as that for the turret.

LOCOMOTIVE AT THE COLUMBIAN EXPOSITION.

ENGINEERING. Cylinders ... • •• • •• . . . 19 in. in diam.

by 24 in. stroke Drivers .. . . .. . .. ... .. . 86 in. in diam. Driving wheel base . .. ... . . . 8 ft. 6 in. Total wheel base .. . . . . . . . 23 , 11 ,

, weight of engine in working order . . . . . . . . . . . . . ..

Weight in working order on drivers , on truck ... .. . . .. , of tender. . . . . . . . ..

Total w.:ight of engine and tender ...

124,000 lb. 84,000 " 40, 000 ' ' 80,000 ,,

204,000 "

GENERAL SPECII<' ICATIONs ~·on MA·r·EmAL. Boiler Stccl.- All plates for boiler t o be of mild steel.

To be of a uniform thickness and free from pitting, scale, or other defects; all sheets to be true and level; any that are wavy or buckled will be rejected. Test piecea to be cut from each sheet, and corresponding numbers to be stamped on each sheet and test piece. T est piece to show an ultimate tensile strength of not less than 50,000 lb. nor more thl!-n 6~,000 ~b. per square inch of original section. El<?ng.a~10n m 8 m. to be not less than 25 per cent. A str1p 6 m. long to be bent over oold until the ends meet each other, and no fracture to appear in the bend.

hould any sheet develop defects in working it will be re­jected.

Stay Bolts an d Braces.-Iron used for sta.y bolts and braces to have an ultimate tensile strength of not less than 50,000 lb. nor more than 65,000 lb. per square inch of original section. Elongation in 8 in. to be not less than 30 per cent. Reduction of area. of fractured section to be not more than 35 per cent.

Stee l Springs.-A ll spr ings to be made of the best crucible cast steel oil tempered. Springs to be guaranteed for one year.

Boiler.-Boiler (see Figs. 6 to 14 on the two-page plate in our last issue) to be of the wagon top type, of the best workmanship and material, and to be capable of carrying with safety a working pressure of HIO lb. per square inoh. All plates to be planed at the edges and caulked with a round-pointed tool.

Thickness of Shuts. In.

Smokebox • •• • • • .. . • • • . .. -A-Barrel -. . . • • • .. . • • • • • • .. . ltr Connection ... •• • • • • • •• • •• -ftr Dome • • • • • • ... • • • .. . .. . ! Front flue • •• • •• • •• ••• • • • 'iulr Back flue • •• • •• • • • • •• • • • ,{if Wagon top ... • • • • • • • • • . .. flf Back ... ... . .. • • • • • • . .. t lr Sida • • • • • • .. . ... • • • • •• l'tr Firebox side . .. • •• • • • .. . •• • lfi Crown • • • • • • ... • • • • •• • •• i Top water arch ... ... ... ... • •• ~~ Bottom water arch • • • . .. ••• . .. fa Throat • • • • •• •• • • • • .. . .. . i

Crown bars to be 21 in number, equally spaced, not more than 4~ in. centre to centre ; to be made of two bars 5 in. by ~ in. best quality iron welded together at ends, secured to crown sheet by twelve ~-in. T -headed rivets passing through wrought-iron tapered washers between crown bar and sheet. The sharp edges of the holes to be chamfered off on the under side of the crown sheet. Each crown bar to be connected to wagon top by four sling ~tays . The endR of crown bars are to be chipped so as to £ t the upper corners of the £rebox and to rest on the side sheets with a good bearing. Where crown bars come under dome, stays are to be run up in dome, as shown on drawing. Between each crown bar is t o be placed a. 11-in. round stay, with ends enlarged to 1i in., screwed and riveted to shell at each end.

F irebox.-Firebox to be 108~ in. long by 40i in. wide inside, set on top of the frames. To be fitted with a. water arch, as per drawing, 4! in. water space. ]firebox ring to be double riveted and finished on sides and corners all around. Water space side and back of firebox 3 in., front 4 in. All stay-bolts to be Falls hollow stay­bolt iron, mandril rolled of the best quality, 1 in. outside diameter, with a -r\ ·in. hole through it. To be out with 12 threads per inch, screwed firmly into sheets and riveted over on both ends. Hole to be reamed out after riveting. Stay· bol ts to be spaced as shown on drawing, with two extra rows at the top. Liner plates to be riveted inside of throat sheet and back head at bottom, as shown for the firebox and frame braces. A liner plate to be riveted to the back head at the top and 3 in. by 3 in. angle irons, to which are secured the longitudinal stays. Mud-plugs and blow-off cock to be located as shown. All plates to be thoroughly annealed after flanging and punchmg.

Dome.-Dome to be 30 in. in. in diameter inside and secured to boiler by fl anging wagon top sheet up into dome and riveting with ~- in. rivets and a double riveted seam on wagon top. Cast-iron dome cover to be riveted to top of dome. Shell of boiler to be of -h in. steel plates of dtmensions as shown on drawings, rolled to a true cylindrical shape. Diameter a:t' . sma.lles~ ring, 58i ~n. Horizontal seams to be all butt·Jotnted, w1th cover strtps inside and out as per detail drawings. L ongitudinal seams to be lap seams double riveted.

\VE continue on our t.wo-page plate this week the P';lb­lication of details of the expre, s passenger locomot1 ve built for the eighteen hours' journey between New ~ork and Chicago on the New York Central and Hu~son ~1ver Railroad and we give the £rst part of the spectficat1vn to which th'e engine was builb.

Fuel . . . . . . . . . . . . . . . bi tumino~s coal Gauge . .. . . . . . . .. . • . • 4 h. 8~ 10.

Front and baok flue sheets to be thoroughly stayed with 1l -in. round Rtays secured by l·in. pins to crow feet at both ends. All pinA to be held in place by spring cotters. All stays to have a good bearing on pins, and to have no lost motion when put in place. The flat surface a.t the junction of barrel and wa~on top to be stayed with one piece of 4 io. by 4 in . angle-tron and three cross·stays of 1t-in. round iron.

Flues to be 2 in. in outside diameter, 11 B. W . G., 145 in. long, of the besb quality steeL Number of flues 268,

•

359 pitch 2U in. Flues to be set with copper ferrules at both ends expanded into flue sheets, r d both ends beaded over. The sharp edges of the hole~:, n flue sheets to be chamfered off on botl:i sides.

R ivet holes to be accurately punched, so that when sheets are laid together the holes shall cQincide. Holes to be so punched that when the sheets are laid together the smallEr diameters of the holes shall be together where the sheets touch each other. In case holes do not coin­cide, they are to be rea.med out so a.s to bring them fair. In no case is a drift pin to be used.

Smokebox.- Smokebox to be of !-in. iron 56 in. long. To be air-tight, and to have a wrought-iron ring riveted in at the front end. Cast-iron front frame for smokebox door to be secured to this ring by studs, to be fitted with a perforated steel plate spark-arrester closely fitted around steam and exhaust pipes, arranged as hown on Fig. 3. Size of perforations in plate, l~r in. by 1! in. A deflector plate to be fitted in smokebox, with mov­able slide, operating from the cab.

Furnace Door .- Furnace door to be of i -in. boiler plate, with damper in door and defleetor plate inside. Latch arrang_ed with notches to hold door partially open.

F1·ames.-Frames to be of the best hammered iron ; main frame in one section with brace welded in. For­ward section securely bolted a.nd keyed to main frame ; frame to be finished all over. P edestals protected from wear by cast-iron shoes and wedges, and looked together at bottom by If-in. bol t through thimble. Wedges and shoes furnishea with bolts to hold them in position in pedestals ; wedges adjusted by .screw passing through slot in thimble, with nut above and below thimble.

Fra,me and Boiler Braces.-Frame braced at back end. Expansion knee to be bolted to the back end of boiler and fitted und~r cap bolted to the foot-plate. A pad (Fig. 2) to be bolted to each side of the firebox, with a. pin forged on it which receives one end of a supporting link, the lower end of which fits a pin passing through frame. An ex­tension on lower end of link is drilled for the brake-hanger pin. A brace to extend acr:>ss underneath the front end of firebox and to be bolted to each frame by two 1-in. bolts. A brace to extend across front of firebox lipped over, and bolted to frames and fitted to a shoe bolted to firebox.

On the two-page plate of our present issue we publish some further details of engine 999. Figs. 21 to 24 a.re SE.ctions of the cylinders, valve seat, and cylinder heads ; Figs. 25 and 26 are details of the valve chest ; Fig. 27 shows the valve; Figs. 28 and 29, piston-rod packing; Fig. 30, the cylinder relief valve ; Fig. 31, the main steam admission valve; Fig. 32 is asep!l>rate view of piston-rod; Fig. 33 shows the crosshead ; Figs. 34, ~5, and 36, the guide bars a.nd guide-bar brackets ; F ;gs. 37, 38, and 39 are the connecting and coupling rods ; Fig. 40, eccentrics; and Figs. 41 and 42 are details of the valve gear.

(To be continued.)

R ussiAN RAILWAYS.-The Russian Minister of Means of. Comm.unicat~on has ~pened a. cr~dit of 2,800,000 roubles, wtth a. vtew to mcrea.smg t he rolltng stock of the Vistula. Railway. The line is worked by the Russian GovHn· ment.

FRENCH MECHANICAL INDUSTRY.-Tbe profits realised by the Cail Company-an old-E'stablished Parisian mecha­nical undertaking- last year admitted of the distribution of a. dividend of 16s. per share. The council of administra­tion carried, at the same time, 10,000l. to the contingency fund, and applied 8000{. to the redem ption of the cost of sundry new works; an allocation of 869l. was also made to the reserv~ fund. The company has received some important orders from the French Admiralty; these orders have rendered it necessary to extend and improve the appliances at the St. Denis works.

---THE Nxw ARMAMENT OF H.M.S. "DEVASTATION.''­

Tbe Devastation has completed her gunnery trials. The mountings for the 10-in. 29-ton breechloaders in the turrets differ from all others hitherto supplied to the Navy in the arrangement of the recoil appointments. The new guns have a total length of 342.4 in., a length of bore (in­cluding powder chamber ) of 320 in., and a. diameter of 43 in. at the breech tapering to 16 in. at the muzzle, and they fire a projectile wei~hing 500 lb., with a full charge of 252 lb. of prismatic brown powder. The muzzle velocity is 2040 ft. per second, and the muzzle energy 14,430 foot- tons. In the Devastation the turret armament is worked entirely by band, and in consequence the guns can be loaded at any time and in any position. The turrets, however, are rotated by steam, and during her refi t a duplicate turning engine has been attached to each turreb as a precaution against accident. Four rounds were fired from each of the eight 3-pounder Hotchkiss quick-firing guns. Three rounds were afterwards fired from each of the guns in the fore and after turrets, two independently with reduced and full charges, and the last from each gun simultaneously with full charges. The elevation rose from horizontal to as much as 13 deg. ex­treme elevation, while the bearings varied from abeam to 10 deg. before to 20 deg. abaft the starboard snd port beam respectively. A number of misfires occurred, owing to the use of wire tubes, and in the fore turreb there was a little scoring of the brake piston by the glande, w hi eh caused some delay. The trials, however, passed off wit h remarkable success. The recoils from all the guns remained uniform at 36! in. with full, and at 36t in. with reduced charges, while the graphic lines and cur"es of recoil pressures showed that the action of the bar reguht­ing the influx of water in the brakes was particularly steady. The under-water torpedo gear was subsequently tested by Captain Hall, of the V ernon.

"'60 .)

ROTARY DUMP

E N G I N E E R I N G. [SEPT. 22, 1893.

CAR AT THE COL UMBIAN EXPOSITION.

CONSTRUCTED BY THE BLOOMSBURG CAR COMPANY, BLOOl\IISBURG, PENNSYLVANIA.

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THE car we illustrate on the present page is of interest, in that it combines in itself the advantages of a side and end tip dump car. ' Vith this object the body of the car is attached by a. hinge to a cross beam as shown by :Fig. l, which in turn is mounted on a swivel on the under body of the wagon, and by means of a stout wooden beam the whole upper body can be rotated round the axis of the swivel, and thus brought into the most convenient position for tipping. As will be seen from Figs. 2 and 3, the hinge on which the body of the car rests is not under t he centre of the car , but to one side. The surplus weight t hus produced on one side of the hinge is transferred by a couple of cross beams to that used in the operation of rotation, and the for­ward end of this is supported by a bar. iron st rap. To insure against accidental tipping, the forward end of t he car is locked down as shown in F ig. 2. The car, we may add, is built under the patents of Mr. J. H. Lockard, by the Bloomsburg Car Company, Blooms­burg, Pa., U.S.A. The same company also manufac­ture ordinary freight cars, the special feature of which, the brake gear, is shown in Figs. 4, 5, and 6. From these engravings it will be seen that every wheel of the truck is braked, each separate brake shoe being carried on a. separate lever, one end of which is attached t o the truck body, whilst the brake rods are fixed to t he other ends. The shoes are placed outside the wheels instead of between them, as is more usual, and the levers carrying them swing in a horizontal direction. The only other special feature of the car is the bolster built up of steel !-beams, in place of the more usual wooden one.

SCREW ELEVATOR GEAR. TIIE elevator gear which we illustrate on the opposite

page is made by the Standard Screw Elevator Manufac-

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RaTING MACBINERY.-The valuers to the Chesterfield U nion (Messrs. Hedley and Co.) lately revalued the fa.ntory of Messrs. Hewitt, Bunting, and Co., increasing the rat ing from 84Z. to 460l. Seeking the aid of the Machinery U sera' Association, the firm were advised to appeal. The

result so far is that th9 Assessment Committee at the hearing on Thursday of last week, when the a.pp~lla.nts were represented by Mr. Humpbreys-Da.\·ies, reduced the new valuation of 460Z. to 1G8l. ; but as even this amount is believed to be ex{'essive, a. further appeal is to be made to the sassions. These appear to be some of the results of attempting to rate machinery.

AMERICAN GuNDOATS.-The U nited Rtates Navy De­partment has issued advertisements for the construction of three gunboats, which are to be of 1200 tons displace­ment, have triple-expansion engines, and be capable of attaining a speed of 15 knots per hour. They will be practically of the same type as the Bennington and the Yorktown, although somewhat smaller, and they are intended for service in Chinese waters. The department reserves the right to award a contract to any bidder, regardleos whether or not the tender is the lowest sub­mitted. This is done in order to make a more equitable distribution of the construction of warships among the shipyards of the United States.

CLYDE NAVIGATION.-The quarterly report by the engineer to tbe Clyde Navigation, Mr. J ames Deas, C. E. , Atates that 498,180 cubic yards were dredged from the river, more than half of which was taken from the new Cessnock Docks. The construction of the walls of this dock is progressing satisfactorily, and over GOOO lineal feet were completed at the date of the report. Into these walls therA have been worked41,845cubicyards of rubble 15,706 cubic feet of granite ashlar, 216,373 cubic feet of concrete ashlar, a.nd 24,229 cubic feet of granite cope. The sheds for the docks are to be of two storeys, and out of a. total of 1156~ ft. sanctioned, 684t ft. are in progress. A large graving dock is being constructed clo~e to the entrance to the Cessnock Tidal Docks, and 101,397 cubic yards have been excavated in preparation for the con­struction.

SEPT. 22, 1893·] E N G I N E EiR I N G.

SCREW ELEVATOR GEAR AT THE COLUMBIAN EXPOSITION. CO N ' TRUCTED BY THE STANDARD SCRE\V ELEVATOR COMPANY, NE\V YORK AND BALTIMORE.

( Fo·r Description, see opposite Page.)

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THE TRIALS OF THE SPANISH CRUISER "INFANTA MARIA TERESA."

THE new Spanish cruiser Infanta. Ma.ria. Teresa, built at the Astilleros del Nervion, Bilbao, went out from Ferrol on her official natural draught trials on Monday. This \easel, which we fully described in last week's issue (page 338 ante), is the first of three constructed at this new establishment. The dra.ught of thP, vessel in a. preceding trial was 21 ft. 6 in., the displacement being 6890 tons. The vessel steamed for eight hours at sea, with a heavy swell running in from the Atlantic, and the results were extremely satisfactory, fa.r exceeding expectations, while every­thing worked splendidly. The fa.ns were kept run­ning merely for efficiently v&ntila.ting the stokehold,

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and the pressure recorded by water gauge was 1~ in. Of course there was no difficulty with tubes. A plentiful supply of steam was maintained at a. mean pressure of 145 lb. per square inch. The meo.n power of the half - hourly records of the engines wa.s for the starboard set 4686 indicated horse­power at 105 revolutions, and for the port engine 4872 indicated horse-power at 106 revolutions, a. total of 9558 indicated horse-power. The vacuum was 27! in. The method taken to arrive at the speed of the ship wa.s ¥ follows : The vessel ran over the mea­sured mile four times before a nd four times after the run at sea, during which runs the Naval Com­missioner from Madrid ascertained the number of revolutions corresponding to one nautical mile. The a.vera.ge number of the eight runs on the measured mile was adopted as the means of ascertain­ing the speed of the vessel in nautical miles during the trial at sea. The speed worked out at 18.48 knots. The highest speed record wa.s at the rate of 18.8 knots . The guarantee was 18 knots, so that the result is most satisfactory. It may be added that if the mean speed a ttained by the vessel at the trials had been less tha.n 18 knots, without falling below 17! knots, the vessel would have been accepted only on payment by the builders of 80,000 pesetas for each complete tenth part of a. mile per hour that had not been attained. The vessel is to proceed on her forced-draught trials forthwith, when a speed of 20 knots is to be main­tained for four hours a.t sea.

NOTES FROM SOUTH YORKSHIRE. SHE~'FIELD, W ednesda.y.

William J essop and Sons, Limited.-Tbe direotors of this company have declared a.n interim dividend for the past ha.lf-year of 15s. per sba.re, equal to 5 per cent. per annum.

Iron and Steel Trades.- Th e history of the iron trade during the pa.st quarter of a century does not show such a. deadlock as at present exists. Inquiries with a view to the :placing of the forthcoming qnarter's contracts a.re commg into the district, hub cannob be dealb with, as there are no permanent quotations on which to form a basis for negotiations. Almost all the blast furnaces a.re

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damped down or blown out, owing tlo the coke supply being exhausted, and thousands of ironworkers a.re idle. There are some fair supplies of forge and foundry pig, but consumers are doing nothing. In manufac­tured irons there a.re larger inquiries for best and medium qualities of bar for South Africa. and Aus­tralia, but prevailing high rates, known to be only tem­porary, check business, and. the. orders a.re either held over or sent to compet1tors 1n the north or on the Continent. It is felt tha.t severe permanent injury is being done to the local iron and steel industries. Those engaged in the heavy steel trades a.re experiencing re­verses and losses. More than one· ha.lf the mills are idle for want of fuel. At the same time there are evidences of a further improvement in the ca.ll for marine ma.teria.l, hub nob a.b the enhanced values quoted within the past month. Manufacturers ba.ve to stand idly by a.nd be passed over. As to any improved trade in railway material, that cannob be looked for for a long time, a.s, after such heavy losses in revenue, the home companies are sure to pursue a policy of rigid economy. Orders for t~res, axles, and springs may, however, be looked for on East Indian a.nd South A fric:an accounb. Agents of Bessemer billets a.nd slabs find very little demand at present rates, 5l. 17s. Gd. to 6l. lOa. per ton, and are mostly delivering on old con­tracts, without attempting to force new business. llouses engaged on a.rmour-pla.tes and ordnance a.re slack. En­gineering £rms a.re suffering severely. Besb qualities of crucible cast steel are selling well for the U nited States, ~outh Africa., India, and the Continent.

Tke Coal Cri&is.-Fortunately, durin~ the past few days there ha.ve been no further scenes of dtsorder in the dLB· trict, though some very threatening language ha.s been used with regard to the intrC'duction of Durham coal. As a. result ma.ny £rms a.nd agents have cea.sed to imporb it. With engine slack fetching 17s. Gd. to 20s. per ton, ma.ny manufacturers have ceas£d to use it, and have "set down " their establishments. House coal fetches 25s. to 30s. per ton. Around L eeds the deu-th of fuel is greater than in the neighbourhood of Sheffield. Near the latter town there are ma.ny large stacks of coal, but the colliers will not allow them to be removed, a.nd to endeavour to do so would only lead to renewed rioting. It was noted last week tha.b a. large section of the miners here a.re in favour of reanming work ab any of the collieries where the old ra.te of wages is offered. As the distrflss in the

F.

ranks becomes daily greater, this opinion is more openly expressed, and if a ballot were taken this week there would be a majority in favour of it. The miners' leaders in this and the neighbouring districte advise the men to work at the pits where no reduction has to be submitted to, and unless some settlement is effected very shortly, there is no doubt this ad vice will be acted upon by a large section of the men.

H ull Export Trade Crippled.-The seven weeks' strike has bad a marked effect on the trade of the port of Hull. Stocks in the various depots for manufacturing and domestic purposes are exhausted, and no Yorkshire coal is obtainable. Prices are of an extraordinary character, 24s. per ton having been realised for best South York­shire steam bards, as against l !ls. 6d. six weeks ago. Usually this is the best time of the Hull shipping season, a rush being made consequent on the early closing of the Baltic. I t is coml?uted that the port has already lost lOO,OOOl. by the strike.

NOTES FROM CLEVELAND AND THE NORTHERN COUNTIES.

MIDDLESBROUGH, W ednesday. T he Cleveland I ron Trad.e.-Yesterday there was not

a numerous attendance on 'Change, and the amount of business transacted was not large. What transactions occurred were mostly for immediate delivery, buyers pre­ferring to purchase only what they need for immediate requirements, believing tbat quotations are likely to decline a little. Makers were pretty firm in their figures, and asked as a rule 35s. 6d. for prompt f.o.b. delivery of No. 3 g.m.b. Cleveland pig iron, but sales were recorded at 35s. 4~d., and the latter price was generally asked by merchants. Th~ lower qualities were a trifle easier, and 33s. 9d. was named for No. 4 foundry, while for grey forge 32s. 9d. was mentioned. Several sellers, however, held out for 3d. per ton above these quotations. Middles­brough warrants were 35s. 4d. cash buyers. L ocal hema­tite pig iron was reported in fairly good request, and 433. 6d. was about the price for Nos. 1, 2, and 3. Spanish ore was not altE:red. T o-day our market was quiet, with little business doing. Quotations did not change much, but one or two parcels were disposed of on rather easier terms than on the previous day. No. 3 was said to have been bought at 35s. ~d., but most sellers asked 35s. 4!d. No. 1 Cleveland pig was obtainable at 37s. od. Middles­brough warrants closed weak at 35s. l~d. cash buyer~.

Ma;nufacturcd Iron a;nd Stetl.-Little change has taken place in the manufactured iron and steel industries durio~ the week. One or two firms are asking a trifle higher prices for certain classes of material, and works are well employed, but on the whole the tr~des may be said to be practically unalter~d. Common tron bars are qu<;>ted 4l. 17d. 6d.; iron shtp-plates, 4l. 15s. to 4l. 17s. 6d.; Iron ship angles, 4l . 12s. od.; steel ship-plates, 5l. 5.s.; and steel ship angles, 4l. 15a. -all less the usual discount. Heavy steel rails are 3l. 17s. 6d. net ab works.

Board of A?·bil1'ation.-At a meeting of the Board of Conciliation and Arbitration for tbe manufactured iron and steel trades of the north of England, held on Monday a letter was read from the Midland Iron and St~el Wages Board with respect to the pro­posed amalgamation of the Midland and Northern sliding scales. The board considered that they were nob in a posi­tion to discuss the question that day, but the operatives and employers were to consider and report to a future. meet­ing of the board. The president (Mr. Wm. Whttwell) said the employers wer.e r%dy to agre~ to the !enewal of the sliding scale, With three excepttons, wh10h only affected 2 to 5 per cent of ;;he whole output. These works were the Stockton Malleable, the Spennymo?r, and Jarrow. The machinery of the board was suffiCient. to deal with the matter. On Mr. Trow (the operattve secretary) stating- that it wo';lld be necessary ~o have meetings of the m~n at the v~r10us works to . consider the matter, ib was deCided to adJourn the meetmg fo~ three weeks, wages to continue on the old scale for that time.

Sir W. G. A.rmst1·ong, Mitchell, a_nd Oo., Lilm.it~d.-In their eleventh annual r eport the duectors of this com­pany propose the payment of a dividend of 10 per cent. per annum on the ordinary stock and 4 P.er cent. o~ the preference shares of the company (less mcome-tax), of which 2~ .and .2 per .c~nt. respectiyely have already been paid as mterim dividends. This leaves a balance of 2255l. 7s. lld. to be carried to next year's account.

Palme1·'s Shipbuildjlng and ,Iron Co:mpany. -The ~nnual report of Palmer's directors IS unsatisfactory, bu.t 1t con­cludes with the remark that prospe~ts as to pnces and

• orders are more encouragmg.

NOTES FROM THE SOUTH-WEST. Cardiff.-The demand for t~e be~t steam .c?al has been

in exces·s of the supply, but mferio~ q.uahttes have not sold so readily. The best descnpttons have made 14s. 9d. to 15s. &I., and secondary ditto .133. 6d . to 14s. 6d:

er ton H ousehold coal has been m good request, ~ o. 3 Rhondda larg~ has made 15s. t~ 15s. 6~. per ton. Coke has been in fair demand at pr~viO?S pnces. Iron

h ruled firm the demand havmg mcreased. The i::n :~d steel trad~s have presented a slightly better tone; heavy section steel rails have made 3l. 15s. to 3l. 17s. 6d., and light section ditto 4l. 15s. to 4l .. 17s. 6d. ~er ton.

Devonport.-Improvementsare bemg made 1~ the dock· ya.rd smitheries at Devon:port in accordance w1th sug~es­tions from the master smttb, Mr. W . C. Thomas. ne of these improvements is Mr. Tho~as's new type ~ ~ot and underg?ound furnaces, specially constructe or

E N G I N E E R I N G. [SEPT. 2 2, I 893. modern smithing. The advantages claimed for this underground furnace are that greater facilities are given workmen for producins- superior work, while a consider­able saving is effected m fuel.

--forenoon, 1000 tons being dealt in at 35s. 4~ :1. per ton cash, and 35s. 6d. one month. The settlement prices at the close were-Scotch iron, 42s. 7 !d. per ton; Cleveland, 35J. 3d. ; Cumberland and Middlesbrough hematite iron, re•pec­ti vely, 453. and 43s. 4id. per ton. Business was again somewhat inactive on Tuesday forenoon. Some 8500 tons of warrants were dealt in-7000 tons of Scotch and 1500 tons of Cleveland-a.nd each recovered ~d. per ton. The market was steady in the afternoon, at 42s. 7~d . per ton for Scotch iron. About 5000 tons were deal t in. Business was also done at 42s. lO~d. one month open, and 43s. 1d. one month with a call. At the close the settle­ment prices were-Scotch iron, 42s. 7!d. per ton; Cleveland, 35s. ~d. ; Cumberland and ~1iddlesbrough hem'l>tite iron, 453. and 43s. 4~d. per ton. The market was quiet this forenoon. About 6000 tons changed hands-5000 tons of Scotch and l 000 tons of Cleveland. One lot of Scotch was sold at 42s. 7d. one month, with 1s. forfeit in seller's option. Scotch lost i d. and Cleveland 21. per ton. The afternoon market was dull, and prices declined a li ttle. The closing settlement prices were-Scotch iron, 42s. 6d. per ton ; Cleveland, 35s. l ! d.; Cuwberland and Middlesbrough hematite iro~, respectively, 45s. and 43s. 4~d. per ton. There are RtJll only 39 blast furnaces in actual operation, as compared with 78 at this time last year. The shipments of pig iron from all Scotch ports last week amounted to 5568 tons, against 7138 tons in the corresponding week last year. Tbey included 300 tons for the U nited States, 490 tons for Canada, 180 tons for India, 2(i6 tons for Australia., 177 tons for France, 445 tons for Italy, 311 tons for Germany, 1028 tons for RusRia, 390 tons for Holland, lOO tons for Belgium, smaller ~uantities

A New Wel~h Company.-The New Albion Steel Works Company, Briton Ferry, has b~en registered. The object of the company is to lay down a plant for the manufac­ture of steel tinplate bars by the Siemens-Martin pro­cess, and to meet the increased demand occasioned through the erection and extension of tinpla te works in Briton Ferry and the neighbourhood.

T he "Cambrian. "-On Tuesday, the Cambrian, cruiser, launched from Pembroke Dockyard in January, made an eight hours' trial of her engines with natural draught, the speed attained being upwards of 20 knots per hour. The ship was in charge of Staff-Commander Stevens, R .N. The vessel steamed away near to the D evonshire coast, her steaming qualities giving satisfaction to the Govern­ment officials, as WE'll as to the contractors for the machinery, Messrs. Hawthorne, Le~lie, and Co. The engines developed 9000 horse-power under forced draught and 7000 horse-power under natural draught. The ve~sel is being rapidly pu.shed forward to completion.

The "Forth. "-Th~ fractured stem of the Forth, cr uiser, is b~ing repaired at K eyham smithery, under the supervision of Mr. W. C. Thomas.

The Glamorganshire Oanal.-A new steam barge made its first trip upon this canal on Tuesday, and reached Pontypridd early. She was discharged and reloaded, and left Pontypridd Wharf again at 2.40 p.m., arriving at Llanda.ff at 7.30 p.m. This wa'3 considered eminently satisfactory, in view of the present condition of the na:vi­gation. When certain dredging improvements are carr1ed out, still better results are expected to be attained.

for other countries, and 1499 tons coastwise. 1he stock of pig iron in Messrs. Connal and Co.'s public warranb stores stood at 333.673 tons yesterday afternoon, as com­pared with 331,347 tons yeste~da.y week, thus showing a decrease for the week amountmg to 674 tons. Glou,cester Bridge. - The Gloucester authorities have

expressed their willingness to raise t be bridge which has hitherto been a discouraging obstacle in the way of dire<?t communication between Cardiff and the Midlands. It 1s proposed to raise the bridge to the extent of 3 h ., so as to secure a clear bead way of 21 ft. for passing vessels. This, it i3 believed, will meet the ncee:;sities of the case.

The Se-t,ern.-On Saturday, Mr. J. M 'Gregor, of London, made a final inspection of the Severn, from Sharpness to Cardiff. Mr. M'Gregor and several other gentlemen left Cardiff Pier-head in the steamtug Bantam Cock at 7 o'clock, and proceeded to Sharpne~~, where they arrived at 10. They left Sharpness agam at 11, having in tow a vessel of 1500 tons, and they rea?hed Cardiff at 2.30. Mr. M1Gregor appea-red to be entirely satisfied with its suitability.

P ortsmouth Docks.-Conside~able P.ro~ress has been made during the past month With prehmmary work con­nected with the construction of two new docks at Ports­mouth. Messrs. Price, of Westminster, h~t.ve secured the contract and the firm is employing some hundreds of local wo;kmen. Each of the new docks is to be 600 ft. in length.

The Bristol Channel. - Messrs. Ed wards, Robertson, and Co. have purchased ~nother steamer for. the Bridtol Channel service. She IS named the Scot1a, and she formerly belonged to the Caledonian Railway Company, which ran her between Ardrossan and Arran. She wa.s built in 18 0, and she is sufficiently powerful to make .a. trip in the Bristol Channel in any weather. Her speed IS

15! knots per hour. Her length is 211ft. , and she will c:arry nearly 700 persons.

NOTES FROM THE NORTH. GLASGOW, Wednesday.

Glasgow Pig-Iron Market.-The market was a little more active last Tbureday forenoon, wh~n there were about 5000 tons of Scotch warrants disposed of at 42s. 8~d. cash, 42s. 11d. one month, and 42.'3. 8d. one month with a. "plant." Of Cleveland there were 2500 tons sold, and the cash price at 35s. 5d. rose ~d. per ~on. The market opened firm in the afternoon, Scotch Iron ohanging hands at 42s. 9d. cash and 42s. ll! d. one ~onth. About 7000 tons were dealt in, and the cash pnce was ~d up from the forenoon rate at 42s. 9d. sellers. Ex­official dealing took place at 43s,. and 42s. lld. one month. with l s. forfeit in buyers' optiOn. About 1500 tons of Cleveland iron were d?ne at 35s. 4d. pe~ ton cash. The closing settlement prtces were-Scotch uon, 42s. ~d. per ton· Cleveland 35:s. 4-!d. ; CumbBrland and Mtddles­bro~gh bematit~ iron, respectively, 45s. and 43s .. 4-!d. per ton. There was a somewhat ~rm market. on F nday fore­noon, and the business done m Scotch u on sh.owed ap advance of ld. to l~d . per ton on the precedmg day s

rices. The cash price opened at. 42s. 10~d. ~or Sco~oh hon. In the afternoon the quotatiOns fell agam_, lea:vmg off 1d. per ton low~r. Qlevela.nd and hematite 1rons remained unaltered m pnce. . At the close the settle­ment prices were- Scotch uon, 42s. 9d. per ton; Cleveland, 35s. 4~d. ; Cumberland and l\1iddlesb~ough bematite uon, 45s. and 43s. 4~d. per ton respectively. The market was quiet on Monday forenoon, when a~out 4000 tons of Scotch and 3000. tons of Clevela~d l!On changed hands the former losmg id. per ton m prtce, and the latter ~aking ~d. . In the n:ttemoon the market was rather easier Scotch Iron opemmg at 42s. 8~d. per ton next day, while 42s. 7id. was subsequently don~. A thousand tons were likewise sold at 42s. lOd. Friday, with a call and a transaction took plac~ at 43s. O!d. on month, with 7~d. forfeit in bu:yer 's ~pt10n. N?b mor.e than 5000 tons changed hands, mclu?mg ex·offiCial busi­ness, the cash price at the last! s~owmg a. drop of ld. per ton from the morning. Cleveland tron also fell1d. from the

Finished Iron and Steel.-The finished iron trade is gradually becoming active, and some firms are so well supplied with work that they have for the time ceased to compete for fresh orders. Prices are accordingly firm at the late advances, but makers consider them to be too low in view of the high prices of coal. T he demand for shipbuilding steel is increasing, and pl'ices are fi rm on a basis of 5l. 7s. 6d. to 5l. 10s. per ton for ship· plates. It is worthy of mention that the Siemens department at the Glengarnock Steel Works has now begun manufac­turing operations. At no other place in Scotland is steel made both by the Siemens and the basic processes.

The L ocal Ooalmasters and their Worknten.-At a fully­attended meeting of L anarkshire coalma.sters, held in Glasgow this afternoon, the action of the miners in re­sorting to four days a week wa~ strongly condemned, and it was unanimously agreed, if continued, steps should be taken to put an end to it. The Airdrie, Slamannan, and Bathgate coalma.sters also met this afternoon and re­solved: " If the miners reduce their working days below five weekly, wages be reduced at ~nee, but if. the men cont.inue to work five days the quest1on of reducmg wages be postponed." A conference of the miners' representa­tives will be held in Glasgow to·morrow, when the number of days to be worked will be determined.

Steel Company of Scotland.- The annual meeting of the Steel Company of Scotland was held in Glasgow this afternoon, the chairman, Sir Charles Tennant, Bart., presiding. In moving the adoption of the annual report

1 the chairman said that it was not such as they coula have wished, as it showed a small loss as the resul t of the past year's business, instead of a profib. R eferring to the depressed state of tr~de and tc;> tbe keener .compe­tition that bad been expenenced, Sir Charles said that during the year abnormally low prices had been touched, and that whereas in the previous year plates fell in price to 5l. 15s. and 5l. 17s. per ton for Clyde delivery, in the past year they had touched 5l. 2s. 6d. per ton. Angles had fallen from 5l. 15R. to 4l . 10s. per ton. The chairman also referred to the comRetition expe­rienced at the hands of the north of E ngland, and to the fact that the port charges levied by the Clyde Trust had the effect of shutting the Steel Company out of the Belfast market. The company have now a fair amount of contracts on their books and orderd in band and the chairman stated that there was an expec­tatio~ that some advance would be made on the low prices now prevailing.

Glasgow Tram·u:ay Extensions: T enders for N e'w L ines. - In view of their acquisition of the Glasgo~ T ramway system in July next, the Tramway Committee of the Glasgow Corporation are about to make several exten­sions, and tenders have been before them for several new lines. These are as follow: (1) From Gorbals Cross, down Main-street, across Stockwell Bridge, along Clyde­side to St. Enoch-sqaure, with loop lines leading to the temporary bridgA at J amaica-street. (2) From Queen's Park to Mount Florida.. (3) From Bridgeton Cross to Rutherglen Bridge. (4) From Woodlands-road, across the new Woodlands Bridge, to Smith-street, Hillhead. The tenders include the short lines required to lead into the new stables at present in course of erection. It is understood that the lowest offer was about 1G,OOOl. It was made by Messrs. A. J. Faill, and it has been accepted.

The P1·oposed N ew Harbou1· at ICirkcaldy.-The plan of the proposed new harbour at Ravenscraig, Kirkcaldy, has been prepared by Mr. Ha~l Blyth, engine~r ~o the K orth British Railway. Accordmg to the plan, It 1s proposed to inclose the whole space between the present East Pier ~nd Craigendal for the new works, the present harbour bemg filled up and traversed. by railway lines. Starting. from Craigendal, the east pter of the proposed harbour, Rhghtly

curving westward, extends seawards ab?ut 2200 ft. . Of the space thus inclosed, the eastern half IS left as an outer harbour, the western half being occupied by the wet dook, wharve~, &c. The space oovered by the proposed dock is 9 acres · depth of water, 27 ft. ; quayage accom­modation 2550 ft. The dock will be titted up with three coa.i hoists and laid with rails. Dopth at en~ra.nce channel 30 ft. ; being thus the deepest harbour m the Firth of F orth. The estimated ?~st is 3~, OOOl. ~one· half to be provided by the North ~nt~sh R !1.1lway Company and the remainder by looal ca.pttallsts.

FOREIGN AND COLONIAL NOTES. Belgian Coal Exports. - The exports of coal from Belgium

in the fi rst half of this year amount~d to 2,200,861 t o.ns, as compared with 1,!>33, 731 tons 1n the correspondmg p eriod of 1892. Io these t r>tali the exports to F.ra.nce figured for 1,579,822 tons and 1,672.232 tons respectlvely.

Belgia;n Blast Fu~naces.-The number of blast furnaGes going in Belgium a.t the commencement of August, 1803, was 24 while there were 18 furnaces ou t of blast at the same d'ate. The total of 24 representing the furnaces in blast in B elgium at the commencement of August waq made up as follows: Cbarleroi district, 8; Li~ge dist.ri<:t, 12; Luxembourg, 4; total , 2,.:1. The productiOn of p1g.1n B elgium in July was 60,~ol tons, as compared. w1th 64 945 tons in July, 1892. The aggregate output ID the fir~t seven month8 of this ~ear was 439,866 ~ons, as. co~­pa.red with 429,975 tons ID the correspondmg penod of 1892.

Belgian R'!.il Expo1·ts.-Th~ exports of st~el rails from Belgium in the first half of .th1s year were 1~, 117 to~s. as compared with 33.041 tons m the correspondmg p enod of 1~02. The exp~rts of iron rails from Belgium in the fi~st ha.lf of this ye&r were 11.455 tons, as compared w1th 8758 tons io the corresponding period of 1892.

Central .Amer ican Teteg?'llphy.-T elegraphic oommuni­cation has been established between Pa.nama and Capira., and it is expected .that by the close <;>f. th~ year the service will be in opera.t1on through to Ch1.r1.qU1: When a t t- le­grapb line has been completed to Ch1nqU1, on the western limtts of the State of P anama, only an unimportant con­nection will be required to secure a union with the tele­graphic service already in operation in Costa Rica.

Metallurgy i n the Souther~ States.-The produc~ion of pig in the Southern States m the first half of th1s year was 1 064 463 tons, as compared with 1,091,871 tons in the c~rre;ponding period of 1802 ; 782,020. tons in the corresponding period of 18~1 ;, 053,630 ~on s m the corre­spond ing perLOd of 1890; 7 t4,610 ton~ m the correspo~d ­ing period of 1880, and 486,R52 tons ID the corresponding period of 1888 It will be seen that great progress ha been made during the last five years. Alabama figured as follows in the production of each half-year: 1893, 501762 tons ; 1802, 536,627 tons ; 1891, 376,389 tons ; 1890, 463,451 tons ; 1839, 36!,346 tons, and 1888, 169,606 tons.

French Bridpe Bu.ildi;ng.- Two important bridges are about to be built in France, the Oissel and the Mira.beau. The Oissel bridge will involve the use of about 800 tons of iron. The Mirabeau bridge will be built almost en­tirely of steel.

Sandy Hook.-Soma modern ordnance for the protec· tion of New York is now in position at Sandy H ook . It is a. 12·in. gun, weighing 51; tons, and it is mounted on a. Snyder disappearing carriage. It is the firs t 12-in. gun built in the United States. It was constructed at the \V atervliet Arsenal.

New Orleans and Liverpool.-The Newport News Ship­building and Dry Dock Company will construct two 10,GOO·ton steamers for the S outhern Pacific Railroad Company, to run between New Orleans and Liverpool.

French Boilers for a B ritish Vessel.- The L ords of the Admiralty have p laced an order with a. }"rench firm, :1\-IM. Delaunay, Belle\ ille, and Co , for a battery of boilera of the Belleville type for the torpedo destroyer Sharpshooter of 4000 horse· power, now in course of con­struction.

British Enterptise in Suuth Africa.-The South African Public Work-. Corporation, Limited, whteh wasregis tered in January, 18!>3, comprises the following firms: M essrs. Charles Cammell and Co. , Limited, Sheffield ; Messrs. Black, Hawthorne, and Co., Gateshead ; the Gloucester Railway Carriage and Wagon Company, Limited; Messrs. McK eene, Avigdon, and Crawley, Victoria· street, Westruioster; and Messrs. Easton and Anderson, Erith.

German RaU Exports.-The exports of rails and railway m.attriel (such as tishplates, metallic sleepers, &c.) from Germanv in the first half of this year amounted to 62,216 tons. The <"'Orresponding exports in the corresponding period of 1892 were 73,270 tons.

French Atlantic T elcgraphy.-The French Transatlantic (Pouyer·Quertier) Cable Company was worked at a loss of 013l. last year. The accumulated losses stood a.t the close of 1892 at 47,466l. The capital of the company is 1, 680, OOOl. in round figures, and the shares have received no dividend since 1885. rrhere has been a struggle for the control of the undertaking between two groups, one French and the other American. The struggle has ended in a compromise, the Board now comprising members of both groups.

[1'1l/Tll,ig1'ation into the United Statcs.-Tbe total number of immigrants into the United States in the firs t four months of this year was 145,299. The corresponding number in the corresponding period of 1892 was 188,599.

ENGINEERING

It will be observed that the force of t.he immigration wa,·e has sensibly slackened this year.

Nta7a1·a Fa lls.- The N iagara Falls Tu~ne:l and P ower Company, which is t o supply ~uffalo ~v1th powe~ from Niagara Falltt will be runnmg tts machmery early m the autumn. Th~ initial tunnel will provide about 100,000 horsa·power.

Japanese Coal for San Francisco.-It is s tated that an American house has concluded a contract foc 2,5,00,0~0 tons of Japanese coal, to be delivered. at San Franc1sc<? m the course of the next ten years. H ttherto the coal .tm­ported at San Francisco has been principally Austrahan .

P opulcction of Bclgiu.m .-At the close of last year B.el­gium had a populati?n of 6, 1~8,355 .. The number of m ­habitants of the vanous Belgtan provmces was as follows : Bra.bant, 1,136,827; H ainaut, 1.165,881 ; E ast Flanders, 061,007; L iege, 778,724; ' Vest F J.aoders, 74~,291; Antwerp, 726.233; Namur, 330,321; Ltmbourg, 22o,OOO; and Luxembourg, 212,171.

Sp"t-nish Raihtnys.- The Spanish q.overnmernt has granted a conces ion of a narrow gauge hne from Z:1lla to Solares. The concession extends over a t erm of 90 years; it is not accompanied by any subvention or guarantee of interest.

MISCELLANEA. IN July there were on the rail ways of the U ni~ed ~tat~s

80 collis ions 87 derailments, and 6 ve other ac01dentg, 10

wbich 58 pe; sons were killed and 176 injured.

Thirty·one milPs of the New York Division of t~e P ennsylvania Railroad ~re now operated by au~omatJC block signals of the W estmghouse electro·pneumattc type.

\Ve arE> requested t o state that the visit.of t~e Birmi!l~­ham A ssociation of Studf-nts of the Instttutton of Cl v1l ~ngineers arranged for Oct? ber 4 to the Griff Collieries, N uneaton, is postponed owmg to the coal str1ke.

The Stanley Show will take place in t he Agricultural H a ll from November 17 to 25. Besides cycles of all kind~'~, and objects rela~ed t o them, it will compri~e engines, tools, and apphances used by cycle makers m their business.

The ave-rage rainfall for the whole year a~ Calcutta is 64 in., but up to June 20 as much a.s 48 m . had fa1len (against 12in. up.tothesame d ate last ~ear), and.thereh~s been much rain smce. At Bombay 8 m . of ra10 fell m bwo hours on June 21, exceeding any fall previously known.

A R euter t elegram from V ict or ia. British Columbia, dated ~eptem ber 19 Fays: "The British c ruiser Melpo­menP, which returned to this p ort from the south on M onday. st eamE>d dir~c t fr_om Callao t~ Victoria, ~ dis­tance of o\·er 5000 m1les, m 22 days, w1thout makmg a stop for coal. Otficer(J of the Navy consider this a note· worthy achievement, which has seldom been paralleled and never surpassed."

The unemployed agitation in Chicago has resulted in the city taking up a part of the work on the drainage canal. Booths for the registration of applicants for work were opened on the L ake Front on September 3, and about 900 were registered on the first day. The work is to be done through the intermediary of a firm of contractors, who will be paid for all disbursements, with 15 per cent. in addition for supervision and plant.

The Hungarian Minister of Commerce ha.s announced a competition for the designs of two bridges, of 312 and 331 metres span, over the Danube. A prize of 31,000 francs ( 1240l.) will be awarded to the design selected as best, and 800l. to the second . Under certain conditions the de­sign er will be offered the post of engineer to the works, Drawings must be sent in before January 31, 1894, an<! further particulars can be obtained from any Austro­H ungarian consul.

A universal exhibition will be held in the Palace of Arts and Manufacture1 at Madrid from April 1 to October 31, 1894. It will not be divided into nationalitie£~, all goods of the same class being shown side by side. The charges for space will vary from 3l. per square metre ( 10~ square feet) to 2l. Special positions will be on a higher scale. :Further information can be obtained from the Secretary, Palacio de la. Industria y d e las Artes, Madrid, and from the Tran lations Bureau, Newport· street, St. Martin's-lane, L ondon.

H. M. Battleship Revenge will leave Palmar's yard on the Tyne at about 1 o'clock p.m. on October 7. It is only 86 days since the sisGer ship R esolution was deli· vered. The Revenge has only been 2 years and 7 months incors~ruction ; she was launched in 1 year and 8 months after her keel was laid. She has been completed in 11 months from the date of launching. The Revenge has been built and engined entirely by Palmer's Company, who not only built the ship and engines, but manufac­tured all the material of which she is constructed.

It is proposed to distribute p ower from a fall on the River Aar at Wynau, Switzerland. There is some 2000 horse-power available, and it is intended to use two media in its distribution, namely, compressed ai r for distances up to three miles, and electricity up to twelve miles. T he bigh·tenaion curren t will be transmitted by naked copper conductors, carried on Rpecial insl:llators. at a pressure of 8000 volts. In the turbine-house at Wynau will be five compressors capable of furnishing 2500 cubic met.res of air per hour at eight atmospheres pressure.

The Prussian Government has approved Messrs. Siemens and Halske's project! of an electric railroad in Berlin. It will compnse (1) an east and westJ line from the metropolitan station, just west of the Spree, to Char-

lottenburg, entirdy on viaduct; (2) al1~e from the } ' r.ed­richs tra.sse s tation in the heart of the c1t¥~ southerly, a:nd then westerly to the Grunwald suburb. 'i :he ~rst port1on of this will be in tunnel, part of the rest on VJa.duc~, and the strictly suburban portion at street I~ vel. (3) A v1aductJ Hne from the Friedrichstrasse station n0rtherly to Pa.nkow partly on viaduct, and partly ~>n the surface. The gauge will be 4ft. 8~ in., and the he1ght of the card 3.15 metres (10ft. 4 in ).

At the Nykroppa Iron Works,~~ Sweden, steel i.ngots are consolidated by pr~ssure ar1s~ng f_r o~ centrlf~ga.l action. In the centre of the castmg p~t 1~ ~n. uprtghll shaft carrying four arms, to each of wh1ch 1s JOinted an ingl)t mould. The moulds are fil.Jed, and then the shaft is set in mot.ion. As th~ speed mcrease~ the mould.a gTadually move fro~ the vert1cal. to the hor1 zontal po~I­tion, and a. pressure 1s developed 1n t~e fiutd me~al equal to thirty times that due to the head m t~e first. m starJ<:e. This drives out the gases, and producessohd castmgs. T~o circumference of U1e circle described by th~ mould~:~ l S 67ft., and the velocity ~early 10,000 ft . . Per mmutEJ. The inventor of the p rocess 1s Mr. L . Sebemus.

From a paper read before ~he C~ng~ess of Architec:te at Uhicago, it appears that ID des1gmng the woodwork for the buildings a fibre stress <?f 1200 lb. was allowed for white pine beams. A bearmg stress of 300 lb. per square tnch was allowed in a direction p erpendicular to the fibre and or 800 lb. per square inch parallel to the fibre. The'shearing stress with the grain was fixe~ at 800 lb. In compression members 800 lb. per square mch was allowed, where the length of the pillar did not ex­ceen ten times its side, 600 lb. when the length was from 10 to 35 times the side, and 400 lb. when the length ex­ceeded ~5 times the side. In desig-ning t.he iron roofs the limiting stre~s under the combined Eff~cts of wind load, dead load, and snow, was fixed at the high figure of 30 000 lb. per square inch. The material used was steel h~ving a tensile strength of from 66,000 lb. to 74,000 lb. per square inch.

The first te~t of the Holtzer projectiles of Ame1ican manufacture took place at th~ Sandy .hook provmg g-rounds on September 5, with results even more favourable than were expected by the makers. Several da.y::s ago the Mid vale Steel Company, of Philadelphia, owner of the right to manufacture Holtzer project1les for all America., North and South, submitted 73 of its S-in. shell to the Government for acceptance. Two out of the 73 were ~elected for testing. rrhey were fired with a velocity of 1625 ft. per stcond a.t a. 9-in. rolled, oil-tempered, and annealed steel plate. Their v~:loci ty was calcu­lated to be just sufficient to send them through the plate and its oak backing. Both shells went through the plate without seriously cracking it, lea.vi• g a hole as clean as if made by a punch. The first bhell wt-nt on through the Rand-heap back of the plate and was lost in the scrub and &and. The second wa~ dug out of the sand, and delicate measuremet~ts &bowed that it had been " upset " slightly. '!'he projecti les weighed 300 lb. each, and were 28.2 in. long and 7.99 in. in diameter. The powder charge was 100 lb , and the pressure developed in the gun amounted to 23,460 lb. per square inch.

According to a paper by Lieut.enant J acques, publit-hed in the T tchnology Quarterly, the sunpleE>t and most ~fieo· tive method of rf'medymg the want of lovgitudinal s trength in wire guns is to make use of long forged E>teel hoops. He points out that the reduction of weight effected by the adoption of the wire system will neces i­ta.te improved means for taking up the recoil, and that the expression "heavy ordnance" should, in view of the powers developed by the n ew explo ives, be replaced by that of "high power ordnance." \V hen many of the objections to wire· wound guns were first raised, the same facilities did not exist for their construction. Nowadays all welding can be done by electricity ; weak 3pots can thus be avoid~:d, and continuous winding easily bffectt-d. The advantages claimed for the wire system of c"n struc­tion are: 1. That s teel in small sect ions can be obtained that posl'esses greater strength than it is poss1 ble to get in any other form. 2. That each layer can be brought truly to its correct t ension. 3. F laws of manu­facture can be easily detected, and if not discovered are confined to that part in which they exist. 4. 1'he parts of the gun are light, and ca.n be more certainly and ~as1ly produced and assembled. 5. For their manufacture, ex­pensive and complicated plants are not needed.

At the recent International Electric Congress a.t Chicago a new form of ''incandescent " arc lamp was de­scribed by Mr. L . B . Marks, M.E. In this l ~*mp t ho arc is inclosed in a. small envelope of highly refractory glass. 'fhis envelope is closed at the top and bottom by plugs through which the carbons pass, a safety val ve being formed in one of the plugs to prevent any undue pressure obtaining inside the glass. Upon closing the circuit the oxygen. inside is consumed and the gases br~mght to a very h1gh ~empera.ture, at which they main­tam the carbon vapour 1ssumg from the arc. This vapour is d epositE-d in the form of a thin coating on the int~rnal snrface of the glass. It is important that the glMs envelope is a~ small as possible, \lnder which condi­tions the beat usualJy diesipated in the ai r is conserved and raises the temperature of the inclosed gases an d carbo~ vapour. Under these conditions the arc proper becomes scarcely visible, but the entire contents of the chamber seem luminous, giving the appearance of a solid cylinder of light. V ery pure carbons must be used, or the results are unsatisfactory. 'I' he rate of consumption of the carbo~s is, h.owever, g~eatly reduced, th~ negative elec­trode m partteula r la.stmg a. very long ttme. With th is n ew lamp rather less of the total energy expended is return ed as light than with the ordinary arc Lut the efficiency far exceeds that of the glow l amp. '

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E N G I N E E R I N G. [SEPT. 2 2, I 893.

TURRET LATHE AT T H E 0 0 L U M B I AN EX P 0 S I T I 0 N.

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AGENTS FOR " ENGINEERING." Al' TRI ,, Vienna.: Lehmnnn and Wcntzel, KarnLncrstrMse. CArE TowN : Gordon nn<l Gotch. Eor:o;o no u : _J ohn Menzies and 'o., 12, Hanover · ·treet. li"RA~CR, Pan s: .Boy venu nnd Ghevillet , Libra.il'ic Etrangere 22

Rue de la Banq~e; :M. Em. Tcrq uem , 31bis Boule\'ard IIau "m~nn' Al ·o for Ad,·el' ttsemen ls, Agence llava.s, 8, Place de la .Bourse' ( ec below.) ·

OBR\IA~Y, Be! Hr:t : :\lcssrs. A. Ashcr a nd Co. , 5, t;n ter d en Linden. J.etpzlg : F . A. Brockhn.u . Mulhou~e : ll . tuckelberger.

OLA ·oow : William Lo' e, l NDU, Calcu tta: Thncker , ~pink, and Co.

Bombay : Thacker an cl Co. , Limited . ITALY : U. Hoepli , ~[il n.n, n.nd any po t ottice. Ln·~Rt'OOL: Mr ·. Tnylor, l..nncling- ' t.age. M \NCII ESTER.: .John Ilcywood , 1 ~ a. Dean gale. Nsw Ol'Tn WALE ·, .'ydncy: Turner nud H enderson, 16 and 18,

Hun ter -street. Oordon and Gotch, Oeorge·:-.treet. Ql EENijL.\ND ( 'Ot"rll), Brisbnne : Oordon and Ootch

(NonTII), Town~,·i lle : T. Willmetl nnd Co. ltoTT&R o.ut : H. A. Krnmer nnd . 'on . Sol Tll An~TRALI ' · Adela ide: W. •. Rig h\. Uxrr.tm 'T\TE I ~C~\' York : w; H. Wile~: ;)3, Ea t10Lh - ·t t·eet. , Chacn~o: II .. \ . IIolme, 41 , Ln.kcsid e Uuilcling.

\ ICTORI \ 1 ~I KLilOl' ft~ R : Mch allc, ~lullcn nud ' lad e 261/264 Colli ns-·t rcct. Oordon and Golch, Lim ited , Queen-str~cL. '

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CONTENTS. rAGE

British Colonies at Chicago 361 The Tower Bridge ( l llm­

trattd) . . • . . . . . . . . . . . • • .... 353 The British Association . . . . 365 Gieholt's Turret Lathe

(lUtutrattd.) .. ... . ...... 358 Locomotive at the Colum­

bian Exposition (nlua­trated) .. .. .. • • . • .. .. .. . • 359

Rotary Dump Car at the Columbi11n Exposition (I Umtrattd) . . . . . . .. .. . 360

Screw Elevator Gear (1U'U8· t rat cd) . . • • . . . • . • . . . • . . • . 360

The Triale of the Spaoish Cruiser " Infan ta Mari& Teresa " . . . . . . . . . . . . . • . . 361

Notes from South Yorkshire 361 Notes from Cleveland and

tbe Northern Counties .• 362 Notes from the South-West 862 Notes from t he Nor th ....•• 362 Forei~n and Colonial Notes 863 Miscellanea . . .. ... .... ..... 363 The LoPs of H .M.S. "Vie-

toriaa. '' . . • • . . • • • • . • . • • . . . 3t35 Mechanical Science at the

British Association . . . . . . 365 London Water Supply .... 866 Elect ric Forging . . . . . . . . . . 367 The Engineer ing Congress

at Chicago (IUu.atrated). . 367

PAOS Notes . . . . . . . . . . . . . . . . . . . . 369 The Laundry Exhibition •. 869 Notes from the United

States ...... .. ........ .. 370 TheN ew Royal Mail Steamer

'' N ' l " 370 1 e ....... . . . .. ... . Contrac tors and the Admi-

ratty . . . . . . . . . . . . . . . . . . . . 870 Bilbao Harbour Works (ll­

lustratt.d.) . • . . . . . . • • • • . . 371 Portland Cement ...•...... 871 Machine Constr uotion and

Drawing, 1893 (lllus-trau d) . . • • . . . . . . . . . . . . . . 371

.F:lec tric Power Transmis· si on in Belgium.. . • . • . . .. 371

The Sanit..ry Condition of Leicester .. . . . . .. .. . . . . .. 371

The Navy ...... .. . . ...... 371 Concret e Beams • . . • . . • • • • 372 Surplus Value .. .. .. .... .. 372 Launch~& and Trial Trips .• 372 J£lectric Lighting Installa-

tion at the Medical Academy , St. Petersburg 373

Industrial Notea . . ........ 373 The Manufacture and Test-

ing of Portland Cement .. 37' The Disposal of Refuse . • . . S76 " Engineering" Patent Re-

cord (Illustrated) . . .. .. .. 377

With a Two-Page E ngraving of DETAILS OF EIGHT­JYliEELED EXPRESS P.ASSElVGER LOCOJJOTIVE .AT Tli 8 WORLD'S COLUM BI.AN EXPOSITION.

E N G I N E E R I N G .

NOTICE. The New Cunarders "CAMPANIA'' and "LU­

CANIA ;" and the WORLD'S COLUMBIAN EXPOSITION OF 1893.

The PubUsher begs to annoUDce that a Reprint 18 now ready of the Descriptive Matter and Illustra­tions contained In the tasue of ENGINEERING of Aprll 21st, comprising over 130 pages, wtth ntne two -page and four single. page Plates, printed throughout on apectal Plate paper, bound ID cloth, gUt lettered. Price 6s. Post free, 6s. 6d. The ordt· nary edition of the Issue of AprU 21st is out of print. --

NOTICES OF MEETI NGS. TilE !Ro~ A~"D .STEEL. JxSTIT\:TK.-Darlington Meeting (Sep·

tember 26 to 2~ 1Dclustve). The following- pape1's have been off~fed for readtng, though not n ecessarily in t he order given : 1. On the ~lanufaoture of Basic Steel at Witkowitz," by Mr. Paul l{upelwaeeer. 2. "On the Waste of Fuel Past Present and Future, in Smelting Ores of Iron " by Sir' Lowt1hian Bell' Bar t. , l<'. R.S. (Past-P tesident). 3. " o'n lron and Steel at th~ t;hic ,go W~~ld's Fair," by Mr. H . ~auerman, Assoc. M. los t. C. E., F.O.S. 4. On Iron and Steet W1re, and the Development of i ts Manufa.ot~re,' ' by Mr. J . P. Bedson, Assoc. M. Inst. C. E. 6. •· On the So.mp~mg of ~~on Ore," by Mr. T. Cla rkson, Wh . . 'c. , Assoo. :\!. l ost. U.E. 6. On the T udhoe Works of the Weardale Iron and <?oat Company,_ Limited," oy Mr. H. W. B ollis. 7. •· On t he L~\b rag Coal Washtog and Dry Separation Plant at the Nor th Bt t,~hburn Coal Company's R1ndolph Pit," by Mr. James I' Anson. 8. On Car bon m Iron," by Professor Ledebur (Freiberg). 9. "On Suggested Improvements in Connection with t he llanu­h.cture of ~teel Plates," by Mr. William Muirhee.d. 10. " On the I nfl uence of the It ating of t be Rupee on the World's Iron Trade" by Professor Roberts-Austen, 0 .8 ., F.R.S. 11. " On th e La~t Twen ty Years in the Cleveland Mining District," by .ltlr. A. L. Steavenson. 12. " On t he P roduotion of Wrought Iron ln Small Blast Furnaces io India," by Mr. T. T urner , Assoc. R. S. M.-Tues­day, September 26, 10 a . m. , reception of the P resident Council and members of the I nstitute by the cha.irman, Mr. D.~:"id Dale' a_nd members of the Reception Committee. Rea.ding and discus~ stoo .of pape~s: 1.30 p.m., a spec ial train will leave the Bank Top

tatton t.o vtstt the T udhoe teel and l•ron Works of the Weardale Iron and Coal Company, Limited, Spennymoor . Alternative e?'cu reio~ •. 1.60 p.m., a special t rain will leave the Bank Top Sta­tton to va<Jat b'lessrs. Bell .Brothers' Lumpsey Ironstone l\line near Sal~burn , where drilli!lg by h~drautic turbine and petroleum engtnf'S may be seen 10 operatton. 8.45 p .m., oooversazione in the Central Hall, Darlington, by in vitation of Mr. David Dale chairman of the Reception Committee. - Wednesday , Sep~ tember 27, 10 a.m ., reading and discussion of papers. 1.30 p.m., special train from Bank Top tation, calling a t Nort h-road Sta­tion, to Evenwood, to inspect the coal washing and soreE'ning plant now being erected on t he LUhrig system at the Randolph Pit of the North Bitchburn Coal Company. 3.45 p.m., return to ~a~lington by speci~ t rain, calling at North-road Station, tor vtstt to works of Darhngton Forge Company and the Darlin~ton Steel and Iron Company. Alternati,·e excursion, 2 p.m. , vistt to the Darlington Porge Company's Works.- Thursday, September 28, 9. 30 a. m ., closing meeting a t the Mechanics' Institute. 10.40 a. m. , sp ecial tra in from Bank Top Station to Consett, to visit the Con· sett Iron Works. 2 p .m. , luncheon by invitation of the Consett Iron Company. 4.30 p.m., return by special t rain vict Durham, for Yisit to t he Cathedral, Castle, &c. -Friday, September 29, 10.30 a . m. , drive to Rab.v Castle, t he historical seat of Lord Barnard, where lunch will be provid ed in t he Scar t b 1\lemorial H all. Drive thence to Baroo.rd Castle, returning vict Rokeby and Oreta Brid~e.

ENGINEERING. FRIDAY, SEPTEMBER~~' 1893.

THE LOSS OF H.M.S. "VICTORIA." WE are still waiting to hear what steps the Ad­

miralty intend to take for the purpose of trying to restore confidence in the fighting value of our first­class battleships, and to show that t hey are not all liable to the same sudden and unexpected fate as the Victoria, if they happen to be rammed or otherwise damaged in action. A committee has been promised- in qualified terms, it is true- for the purpose of investigating the reasons why the Victoria was sent to the bottom so speedily, whether other ships of her clasR could be as easily disposed of , and whether any steps could be taken to im­prove their safety. This is urgently called for, and we trust that the appointment of a competent and independent committee of inquiry will not longer be delayed.

The matter is very serious, and there can be no question as to the necessity of thoroug~ly .investi­gating the points named, a~d of ~at1sfymg the public at home and abroad, 1f possible, that our first- class battleships are not so frail and untrust­worthy as the Victoria catast~ophe i~s n? w ~ausing many to think. The chief. obJectiOn 1s, we imaaine that some of the officials have been so long trying to prove by argument at;td theory! in long papers and speeches, that Admiralty des1gns are above criticism, that they do not see why even such a mat ter as the loss of a flagship, with more than one-half of her crew, should cause the outside public any uneasiness with respect t o the ships that are left. I t would not be difficult t o frame the sort of answer that would have been made by official orators t o any one who might have been pre-

sumptuous enough to predict beforehand that the Victoria could be sent t o the bottom so easily as she was. The answer would have been ready, crushing, and complete, as based upon the official data and ideas. Yet, after all, when an accident happens, the ship immediately sinks.

Great reticence and patience have been shown towards the Admiralty in this very serious mat ter. It has been felt that sufficient time should be allowed to enable them to ascertain all the par­t iculars of the Victoria disaster, and decide what course should be taken. There were exceptions t o this course in the case of politicians who may have had their own purposes to serve in keeping their names before the public, and did not see why even this tragic affair should not furnish a means of doing it. Prominent among these were Lord George Hamilton, Lord Brassey, and Mr. Forwood, M.P., the last named having sent to an evening contemporary to illustrate his ideas of the cause of the catastrophe, a sketch of t he construction of the Victoria, which was entirely incorrect and mis­leading, and showed plainly that Mr. F orwood did not know what the construction of the ship was.

I t is time now that others spoke out, and that those capable of j udging should require to know how these ships are constructed, whether they can be made safer than t hey are against such a likely form of accident as ramming, or other under-water or water-line damage, and whether the officers in command know the best course to adopt in such an event. The necessity for t his has been suggested forcibly several times by paragraphs in various provincial papers (and last week in a London society paper), which hint that it is not the present Director of Naval Construction who is to blame in the case of the Victoria., but the late Director , because the latter designed the ship. We do not like the look of these paragraphs. They indicate a knowledge of something wrong, and suggest a desire to shift responsibility. If there is to be any blame in the matter, it would surely be awarded to those really responsible for the catastrophe, and this responsi­bility should not be evaded in any way as is un­fortunately too often the case with inquiries of the highest public interest. The paragraphs in question are an argument in favour of an impartial inquiry. The Admiralty must know their duty in the matter, and we trust there will be no delay in ap­pointing a committee such as will satisfy the country that a thoroughly impartial and capable exami­nation of the state of our battleships, and of the steps best calculated to preserve them from the sad fate of the Victoria, will be made.

MECHANICAL SCIENCE AT THE BRITISH ASSOCIATION.

T HE recent Nottingham meeting of the British Association, of which we commence our report on another page, has on the whole been quite up to the average in regard to the success achieved. The weather has been, like all 1893 weather so far, unexceptionable from t he pleasure-seekers point of view, and the number of persons attending the meeting has been very fair, namely, 1661 of all classes. The hospitality of the warm-hearted Nottingham people has largely accounted for this success, and never have invitations been more freely given. It is, therefore, with much regret that we have to notice a partial failure in the section which chiefly interests us, namely, Section G, which is devoted to mechanical science. The attendance in that section has been lamentably small, and we think the reason is fairly obvious ; we will give one instance. As will be seen by our report, two papers were read on refuse destruction. It is a subject peculiarly suited to the meeting of the British Association, and a good discus­sion might have been anticipated. Doubtless many interested in the matter might have attended had they known it was coming forward, but no one beyond the officials had knowledge of the fact. A member largely interested in this question, and who had. read a paper on it l.ast year at the Edinburgh meetmg, only learnt that 1t would be brought forward when the meeting commenced, and the fact that he spoke at all was due to the chance t hat he happened to be present. I t is a fact that no one outside the official circle knows from day to day what subjects are to be con­sidered in the section. In the morning the official journal ia published, Rnd in it is a list of papers, but that is quite too late to call any persons

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from a distance. It is for this reason that the discussion, in Section G are often so barren and perfunctory ; and unles~:; the prvcedure is altered, it really seems as if the section might as well be closed. Such a course would be much regretted, for Section G has leaitimately a fun~tion . which. is. filled by none of

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the purely eng1neermg soe1ebes. We have the Mechanical Engineers, the N a.val Architects, and the Iron and Steel Institute holding country meetings every year, but these all lack the catholicity which is the distinguishing feature of the British Association meetings. The interdepend­ence of the sciences is a point that requires no impressing in the present day. This was a point well brought out by Mr. Head in his presidential address. Engineering merges into metallurgy, metallurgy into chemistry ; geology touches it on one hand, mathematics are its guide and cor­rector, whilst physics are of its essence. E~en biology holds a place in the consideration of the skilled engineer. It is evident, therefore, if engineering is to be practised as a. science, and not simply as an empirical following of trial and error precedent, it is highly desirable that engi­neers should be able to meet the lights of the other sciences we have named ; and no course that could be suggested offers a better means of doing this than the British Association meetings. As a m~tter of fact, even in deserted Section G, there are yet gathered together men of eminence in the engineering world such as one sees at no other meetingg, and their meeting must be productive of good; for instance, one ca.n imagine the wide results that might flow from a chance con\'eraation between Sir Benjamin Baker and Professor R oberts-Austen, and yet we do not know any other gathering of a like nature where such an interview would be likely to be brought a.bou ~.

It is the great virtue of the British Association that it throws men of science together once a year t) exchanga ideas and widen knowledge. It will be distinctly a loss to engineering science if it fails to be represented in the Association. There is, how­ever, more wanted than the presence of a certain number of eminent men to make Section G prosper. Engineering science stands on a different pl.atform t) the other depJ.rtments of the A <:JS'Jciation, inas­much a<3 it is s1 essentially practical-by which we mean it haCJ so direct a connection with our indus­trial life- and its ramifications are so wide and various. A designer of destructors, to take a recent instance, will not sit out a week's meetings to heat watchmaking machinery or germ separators described, whilst tho3e interested in mechanism of the latter kind cannot be expected to throw much light on the former subject. At the meeting ju$t closed a most instructive paper on watchmaking machinery was read by Mr. Hewitt, of the Lancashire Watch Factory. This undertaking represents the beginning of what, it may be hoped, will be the opening of a new era in a once important British industry that has almost left our shores. There are very many persons who would have been glad to have attended the meeting if only to hear and speak on this paper, and yet the discussion was of a most meagre nature, a few words from the Re~order of the section, who is an acknowledged authority on t he subject, being practically the only result. .Had n otice of this paper been sent out t o those hkely to be interested in it, doubtless there would have been an accession of membership to the Associa­tion, and a re1lly valuable discussion before the section.

It is difficult to sugaest a remedy for the defects we have referred to.

0

Of course it is only the permanent officials of the section who can do the work required, and these all hold honorary posts. The three secretaries of the section do a great deal more work than most people would care to do gratui tously, and the thanks of the Association are abundantly due to them for their disinterested labours. Still, more is re­quired. What is wanted is an eng~neer, we~l acqua-inted with the c?urse of progress 1n the engt­neering world who w1ll take care to spread abroad the progrd.mm~ of t he section in 9uarter~ where the information is likely to bear fru1t. I t 1s not suffi­cient to carry on the ordinary business correspond­ence of the meeting, to hang diagram~ on t?~ ~a~ls, and to keep the minutes of the sect10n; ~1~1atlve is also wanted; forethought, and appree1at10~ of what goes to make a really successful gathermg.

E N G I N E E R I N G.

Who should fill this post it is difficult to say. Men of business are to~ much occupied in their own special spheres ; but probably amongst the younger of the engineerh1g professors at our technical colleges-one of those previously engaged in the industrial world of engineering- there could be found the right person. It would be his duty to look out for subjects of interest as they arose, to make suggestion<3 for papers, and to take care that the reading of those papers should be previously announced to all persons likely to take an interest in them ; in brief, he would perform for Section G the functions, in this r espect, that have been so ad­mirably carried out by Mr. Forrest for the Institu­tion of Civil Engineers; and upon which, it may be said, the success of the meetings of the latter society is mainly founded. We think it probable that some one could be found who would be willing to take up the work without pay, a condition necessary to establishment of the post.

The President of the Section, Mr. Jeremiah Head, in his inaugural address referred to the fact that the founders of the British Association doubt­less regarded the field of operations which they awarded to Section G as not less purely scientific than those allotted to other sections; but, as he stated, the practice of the Section has recently been to expend most of its time in the consideration of applications of mechanical science rather than of first principles. This is inevitable. Engineers must be practical, mechanical science must be applied science; but the proper function of the bection is to show how science can be applied, and to lift the engineer's practice from the region of empiricism. Mr. Head sll.ys that mechanical science as studied by Watt was as free from commercial bias as chemical science studied by Faraday. It is a pro­position perhaps open to doubt, but, in any case, we cannot exclude the commercial influence from any engineering question, and all that Section G can do is to hold it in proper control. This is a point we have r eferred to in our report of the meeting, and we need not further enlarge upon it here; but the subject is one which should receive attention. No one could accuse Mr. Head of introducing a commercial bias into his address, and yet it was full of matters interesting in themselves. His com­parison of the natural physical powers of man with those of other animals, and the way in which they are supplemented by mechanical appliances, was ex­tremely suggestive, although we t hink in some details he had not brought his matter quite up to the present day. With a few corrections, how­ever, the 1893 address of Section G will afford a most interesting source of information upon a sub­ject not often dealt with.

LONDON WATER SUPPLY. IN view of the fact that Asiatic cholera seems at

length to have gained a footing in this country, the report of the water examiner on the metropolitan water supply becomes of specialinterest. The average amount supplied during the month of July amounted to 199,563,488 gallons per day, or 37.10 gallons per head. Of this total 55.52 per cent. was taken from the Thames, 25.2 per cent. from the Lea, and the remainder from springs and wells. Under all ordinary circumstances the water supplied from the latter SO'Jrces is above suspicion, as contami­nation of the water from a deep well is only likely to occur during construction; and though it must be admitted that instances of such contamination are not by any means unknown, still the infection will usually only exist for a few weeks at the outside. In all such cases the pollut ion has, we believe, arisen from the almost criminal action of the work­men engaged on the construction works. A bad outbreak of typhoid at Croydon some years ago was, if we remember aright, traced to a workman engaged in sinking a well, and it has been suggested that the recent serious outbreak at Worthing was due to the workmen engaged in constructing the ccnduit tunnel, using the same as a privy. Apart from such accidental causes, which, as already stated, do not form perman~nt sources of contamination, deep-well water may be taken as practically pure. In the case of river water there is much greater likelihood of pollution, and many people are dis· posed to think that wherever possible, river water should not in any case be used for potable pur­poses. This is, however, an extreme view to take. There is no doubt whatever that rivers are in t he long run self-purifying. Even raw sewage, as it comes from the main sewer, would probably prove

[SEPT. 2 2, I 893.

perfectly potable if given a long enough run in the open air, though the length of time required for the purification might be very great, and the inter­mediate stages very objectionable. \Vhen turned into running water of about fifty times its own volume, however, the oxidation of ordinary sewage to a harmless condition takes place without any intermediate offensi\'e stage, and it has been claimed that under such conditions the water is sufficiently pure for a town supply after a run of ten miles. This is, however, as much t oo opti­mistic a view to take as the former is too unfavour­able, and most people would prefer to have as litt le sewage mixed with their drinking water aR is practically possible, but there nevertheless is every reason to believe that the admission of a small quantity of sewage to the upper waters of a river constitutes no serious danger to a town having the intakes for its water supply lower down, though it is certainly preferahle that no such contamination should exist. That this is so is fortunate for London, as it must be absolutely impossible to completely exclude organic contamination from a river that flows through so thickly populated and so generally cultivated a country as the valley of the Thames above the companies' intakes. There is no doubt, howevet·, that the Conservancy does an immense amount of good by the care it takes to re­duce the pollution to a minimum. The less sewage that passes into the river, the more quickly and thoroughly it is destroyed. If any considerable per­centage of unpurified sewage passes into a stream, a very much greater time in proportion to the amount present is required for the purification than when only traces of contamination enter the river. The experience of Hamburg last year was a striking in­stance of this fact, though probably if the water had been filtered the consequences of the pollution would have been much less serious. At the least, filters must remove a large proportion of the bacteria, and indeed experiment shows this to be the case ; further, if the filtration is intermittent, or if the filter is well supplied with oxygen by other means, there is strong evidence of an actual destruction of the bacteria. In London filtration has been the rule, aud its efficiency is well shown by the low death-rate from zymotic diseases which the statistics show. As carried out by the companies, the report of the water examiner shows a reduction of t he bacte1ia, on the average, to considerably und er 11n;th of their number in the untreated water, and the organic matter is also largely reduced. In too many cases, howeYer, the pure water from t he companies' mains is led into a cistern, often placed in a very inaccessible position , with the natural result that it is seldom properly cleaned, and from this dirty tank the inhabitants of the house draw their drinking supply. Con­sidering the number of these cisterns in use, it is surprising that more ill·health is not caused by them. The remedy for this is, of course, the adop­tion of constant service and an entire clearing away of the old cisterns. The area of constant supply in London is gradually extending, and in a few years' time will doubtless be universal, but its full benefits will not be felt unless the old cisterns are thrown out at the same time.

'Vith these reforms corn pletely finished there need be no fear of disease being spread by the water mains. The reports of the public examiner are uniformly favouraLle, the organic impurities in the water as supplied to the consumer ranging from .034 to .122 per 100,000 parts, and the bacteria numbering at the most 110 per cubic centimetre, and on the average not one·third of this.

After the question of quality, and equally im­portant with it, is that of quantity, and on this head the report of the recent R oyal Commission­a report with which we shall deal at )epgth on an early ~ccasion-is very reassuring. The average amount drawn from the Thames during July last was 110,401,357 gallons, and this quantity can, accord­ing to the report of t he Commission, be increased to 300,000,000 gallons per day, if necessary, with­out reducing the fl ow over Teddington V\7eir below 1000 million gallons per day, and without taking in any obj ectionable part of the tlood water. 'fhe mP-ans su~gested for securing this increase are the construction of storage reservoirs in the valley of the Thames, at no great distance aLove the present intakes of the companies ; indeed, the minimum dry weather flow at Teddington would, under these cond itions, be, in all probability, actua1ly greater after the works thus suggested have beel'l carried out than it is at preEent.. A great advantage of

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S EPT. 22, t893·] E N G I N E E R I N G.

·h. 1 f the 1·mprovement of the L ondon' transformer, or between the exciting machine and t lS P an vr · 1 • ·111 h lt t f

1 · th fact that it can be carried out b1t by the dynamo, 1t Wl ower t e vo age on accoun o ~~fPk~e18iog ~ace with the growth of the _popula- its ~dditional re.sistance, and will . thereby operate

t. ' lp as any scheme for the constructiOn of a agamst the r eqUirements of the process to be per-100 w 1ere B ·d h' d b k ·t · t ' . · onast the 'Ve1sh or Cum berland moun- formed. est es t 1s raw ac , 1 s r ests a.nce goes

resen o1r am b · · • h · t th t ·~- · ··d t · h been suaaested by others must be on n stng w1t Its tempera ure, so a 1" 1s e\ 1 en tams, as as bb ' • -1 1 d t b d t d

· d d the works carried out not for the a r eststance cot so pace canno e use o con-estgne an , . 1 d . . f h It . 1 needs of the metropolis as it at present exists, but for trol the elec_tnca con 1t10~s o t e c~se. 1s a so its anticipated future wants. About t he only part of ~ound to b~ 1ncapable of actmg ~sa ~ehable governor the work which could be constructed for present 1f placed 1n the secondary _Cl~cUlt of the trans­needs and subsequently enlarged in such a case would f?rm~r. Its place, t~e:efore, 1s _1n the shunt-~ou~d be the conduit from the reservoir to the t own. As c1rcu1~ of the exc1~10g machtne, where 1t w~ll reO'ards the L ea valley, about 50,000,000 gallons per energts~ the field cotl s of the generator exactly 1n dao are now taken from this river. Accordin~ to proport10n t o the amount. of e1~ergy called _for by th! Commission, this might be doubled by treatmg th~ bars t_o be heated. It 1s obvwus that th1s _regu­it in the same way as they suggest for the Thames. latmg 1 eststance doe~ not act as an obstruc~10n to From springs and wells about 39,000,000 gallons the useful current ; 1t controls the magnetic field are now taken, but, according to the r eport, of the _alternator, so that when a smal~ amount of 40 000,000 gallons more might be obtained from heat ts needed_, only ~ correspondmgly small w~lls in the Lea valley, and 45,000,000 gallons ~mount of electric power 1s g~nerate~ ~ when the~~ more from the south side of the Thames. Thus 1s no bar to be heated, only JUSt s_uffic1e~t power 1s altogether there is in the immediate neighbourhood developed to overcome the pass1ve res1stances of of London 425,000,000 gallons per day of first-class the apparatus. We are _assured. th_at the ~rrange­water readily available, which would suffice for a ment adopted works sattsfactortl~ 1n practtee, and

opulation of upwards of 12,000,000 at the present thereb:r tends ~o r ende! econo~ucal all the pro­~ate of supply. If a still larger supply_is wanted at ceases tnvolve~ 1n electncal forgmg. . any future date, i t is suggested that 1t should be To further msure economy of workmg, the con-souaht in the valley of the Medway. ductors used t o c~nvey the cu:rent from the trans-

o former to the vanous forges 1n a large factory are copper rods 3 in. in diameter. These are capable of carrying the dense current produced by a gene­rator of 100 horse-power. The voltage and am­perage delivered to the metal-holders by these con­ductors will vary with the bars inserted from 4 to 30 volts, and from 6000 to 10,000 amperes.

ELEOTRIC FORGING. THE method of using the electric current for the

purposes of forging devised by Mr. George D. Burton of Boston, Massachusetts, is among the greater' attractions of the Electricity Building at the Columbian Exposition. Not only ordinary sightseers but en()'ineers and technical people, throng ro~nd these

0

~aily-given illus~rations of the adaptibility of electr1c power to weldmg and forg­ing operations ; and t~ey marvel as. they go away after havina seen thtck bars of 1ron and steel heated up t~ redness, and even to whi~eness, in a few minutes. The metal-holders w h1ch clamp these bars are movable in order to admit r ods of varying lengt.hs ; they are, moreover, so arranged as to allow of two or more bars being heated at the same time. No on e could fail to be impressed with the efficiency of the plant on seeing three bars of iron 4 ft. long and 1 in. by i in. in cross section raised up to forging heat in the space of four minutes. Not lees indicative of the care with which all the electrical and mechanical details have been thought out was the raising up to a working heat in eight minutes of three bars of steel, each 3 ft. long and 1 in. square.

The experiments are not confined to iron and steel, but are extended to brass and copper, and are made to include not only welding and forging, but also brazing, hardening, and tern pering.

The metal is heated not only at the surface, but uniformly and simultaneously throughout its mass. It has been ascertained that electrically heated bars retain their heat considerably longer than when the customary forge is used. This is a valuable advan­tage, as it largely dispenses with reheating while working the metal into the desired shape. Plates, as well as bars, can also be heated and drop or press forged with one heat, while bars of any shape can be heated their entire length, and the blank forged and cut off before being cooled. These instances show that the capacity for work of the machines used, and the processes which may be carried on, are as varied as they are extensive.

The electric plant consists of an exciting machine, an alternating-current dynamo, and a transformer. The dynamo generates a current of high voltage and small amperage. The functi on of the transformer is to deliver a current for heating purposes of low electromotive force and high amperage. It is ob­vious that the condition changes somewhat with the electrical conducting power of the bar. According as its temperature rises, the difficulty of forcin~ a current through it also increases. To meet this gradually augmenting difficulty, the electromotive force must also rise by successive increments. In its turn, this implies a piece of mechanism or some regulating device which will be automatic in its action, and which will modify the current and the electromotive force as required by the varying re­sistance of the bar.

It was quite natural to think of a rheostat or wire resistance to act as governor to such a complicated piece of electric machinery ; but then came the question as to where such a rheostat should be placed. If inserted between the dynamo and the

Eleclric forging is economical, not only because the current is applied just as long as needed, but also because its energy IS expended wholly on the piece of metal, or concentrated on the part of the bar, which may at any moment be in process of operation. In a forge- fire there is evidently a great waste of heat-energy. Be~ides the above, there are other economical considerations in favour of the electric process. Among these we may mention-

!. That no gases are introduced into the metal while heating.

2. That the heat is abundant, and is supplied uniformly throughout the mass.

3. That the temperature can be r egulated to any desired degree from that of the room up to that of fusion, and also that it can be held at any desired point as long as needed .

4. That the bar is always in sight, and overheat­ing can easily be avoided.

5. That many processes may be carried out at one heating, which in ordinary forging would re­quire three or four heats.

6. That more floor space can be utilised, on account of the small size of plant necessary to perform the same work.

7. That the temperatnre of the workshop is not affected by the electrical operations carried on.

8. That instead of having to carry fuel to many fires and r emove ashes, there is but one fire to maintain, viz., t hat under the boiler ; also that there is n o waste of heat by radiation, as in the ordinary forge.

The plant constructed by the Electric Forging Company, B oston, varies with the extent of the installation. Some machines are built which develop 30 horse-power, others 500 horse-power. It may be useful to point out that a given machine will meet all the requirements within its capacity by simply changing the size of the metal-holders, so as to suit the bars of different length s and shapes. It will also be noticed that as the current employed is of low pressure, all danger from shock is entirely removed.

The economical aspects of the question ha~e been studied by Mr. George L. Harvey, a well­known engineer of Chicago, and his r eport shows that, when all conditions are equal, the electrical method of forging metals is considerably the cheaper.

Much credit is undoubtedly due to Mr. Burton f-or having so successfully dealt with the many difficulties of this intricate electrical problem. The details of his work show him to be a sound electrician and expart engineer, and the results obtained augur w~ll for the future of this new industrial application of the energy of the electric currcJnt. It is interesting in this connect,ion to re­call the admirable exhibit of electric welding made by the Thomson-Houston Company, at the Paris Exhibition of 1889, and to note the progress that has been made in four years.

:

THE ENGINEERING CONGRESS AT CHICAGO.

(BY o u R NEw YoRK CoRRESPONDENT.)

(Continued from page 324.) THE next day marked the final session of

both these sections. The firs t paper was . by Mr. E ckley B. Coxe, President of the Mechanl?al Engineers ; it was entit1ed . " A Furnace ~1th Automatic Stoker and Travellmg Grate especially Adapted to Burn the Small Anthracites. " The grate defiligned by Mr. Coxe has transver~e bars with cor.rugated faces, attached to a cha1n belt travellina across the furnace, one end of the return side of the arate beina depressed to dip into a water tank for th~ ashes. l'he author stated, speaking of the possibility of burning anthracite dust, that he had no doubt that dust could be successfully burned but the difficulty Jay in obtaining anthra­cite du~t. Only a very small percentage is obtained from culm heaps, and he doubted whether du3t could be prepared for anything like a reasonable cost. It was further shown that the ordinary dust is un­usually rich in ash ; indeed, a case was noted \'V here the dust was sufficiently argillaceous to yield good firebrick.

Mr. H. Le Chatelier presented " Tests of Hydraulic Materials, " and noted that while great advantages have been derived from the. complet~ investigations and tests made, the growmg multi­plicity and complexity of the proposed tests render t hem impracticable outside of laboratories, and lead to a restricted instead of an increased use of s uch test::a. The paper wa2 prepared for the pur­pose of enlarging the use of met hods of testing by opposing their abuse. The following tests were recommended : 1. Fineness of grinding, according to the r esidue from a 8ieve of 5850 meshes per square inch . 2. Resistance to crushing of cubes 2. 8 in. or cylinders 1 in. in h eight and diameter, composed of one cement and two sand. 3. Invari­ability of volume in boiling water. 4. Rapidity of setting of mortar, one cement to two sand. 5. For the detection of aluminates, to foretell the stability of cement in air or sea water.

In regard to a paper of C. A . Stetefeldt, of Oakland, Cal., entitled " Consumption of Fuel in Taylor Gas Producer Plant," it may be said briefly it was a comparison of statistics between the Marsac mill and a gas producer plant at Aspen, Colorado.

In both mills a Stetefeldt furnace is used for roasting; but the Marsac mill has the old-fashioned revolving dryers, while at Aspen shelf dryers are at hand. At Aspen, separate Taylor producers are provided for the Stetefeldt furnace and the shelf dryers; at the Marsac mill one 7-ft. producer sup­plies gas to both the furnace and the dryers. Hence, in the latter case, the quantity of coal con­sumed for each apparatus can only be estimated, based upon the relative consumption of wood before gas was introduced. According to Mr. vVilson's statement, the relative consumption of wood in the Stetefeldt furnace and the revolving dryers was as 3 to 2.

In the year 1892 the Marsac mill put through the dryers and the Stetefeldt furnace the following quantities of ore and salt (approximate dry weights): Ore, 22,800 tons ; salt, 2262 tons. There were consumed in the Taylor producer 2714 tons of Rock Springs coal. vVe may thus make the comparative estimate as follows :

Marsa.c. A~pen. Difference. lb. lb. lb.

Drying ore and salt S6.G3 72.22 14.41 Roasting ore ... 142.40 117.44 24 96

Totals • •• 229.03 189.66 39.37

The coals consumed at the Aspen and Marsac mills have nearly the same calorific value, as is shown by the analysis.

The Aspen ore contains 6.15 per cent. moisture, and the salt 1. 0 per cent. Accurate statistics r egarding moisture in the ore reduced at the Marsac mill are entirely wanting, but the shipping ore contained 8. 4 per cent. during 1892 ; and it is probable that the milling ore runs about the same as the Aspen.

A considerable difference exists regarding the contents of sulphur in the ores treated, Aspen ore containing 8.1 per cent., and Marsac ore much less. An analysis of an average battery eample for 1891 gave only 0. 7 per cent. of sulphur for Marsac ore. For the output of 1892 no sulphur determination has been made, but since the ore of 1892 came from

-

the lower levels of the Daly mine, it is fair to assume that the percentage of sulphur was some­what higher. The percentage of sulphur is slightly increased by adding pulverised sulphur to the battery pulp before roasting. This, however, is not always done. During 1892, Mr. Lamb says, the average consumption of sulphur in this way per ton of ore was only 3. 72 1 b.

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The low consumption of fuel at Aspen for the chloridising roasting of silver ores is phenomenal in metallurgical history.

In conclooion, the writer would observe that Mr. Morse, at Aspen, experienced the same difficulty in running the Taylor gas producers with coal leav­ing light and infusible ashes (using Sunshine coal alone) as was found in starting the producer at the

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The number of tons of ore roasted in twenty-four hours also plays an important part in the conaump­tion of fuel, an increased output requiring less coal in proportion. The Marsac furnace roasted from 60 to 70 tons of ore in twenty-four hours, while at Aspen as much as 90 tons was put through.

That the shelf-dryers are more economical in fuel than the revolving dryers is self-evident. The ore remains longer in its passage through the former, and the latter lose a large amount of heat by radiation.

All these facts help to explain the difference in the consumption of fuel in the two plants.

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Marsac mill with coal mined at Coalville, Utah. For this reason the Marsac producer is supplied with the dearer R ock Springs coal.

The next paper was '' A Bessemer Blowing Engine, " by J ulian Kennedy, of Pit~burg.

In respect to Mr. Kennedy's paper, which was of great value owing to the author's experience, together with his ability, the appended extract may prove of interest, which follows his discussion of other blowing engines :

'' Figs. 1 and 2 are the plan and elevation, and Fig. 3 is the diagram of air valves and valve gear of a compound horizontal blowing engine, now being constructed by the well-known builders, the E . P. Allis Company, for the Ohio Steel Company. The engine is a Reynolds-Corliss cross-compound; steam cylinders, 40 in. and 78 in.; air cylinders, 60 in.; stroke, 60 in., with reheater in intermediate receiver, and is provided with an independent con­denser. In general design this engine, as will be seen at a glance, is very similar to the large quad­ruple-expansion engine by the same builders to be seen at the Exposition. The air cylinders are so arranged as to draw the air through pipes, which project above the roof of the building, and to dis­charge it below the cylinders. The inlet valve is a plain rotary valve held to its seat by the blast pres­sure, which is admitted to the back of the valve by a. port from the discharge chamber, and is driven from a wrist plate. The outlet valve, as will be noticed, is a triple-ported valve, which is closed at the proper time by the wrist plate.

[SEPT. 22, 1893.

'' The connection between wrist plate and valve is made by a telescopic extensible rod, which pushes the valve shut, but permits the wrist plate to reverse its motion without pulling the valve open. To the valve lever is attached a vacuum pot, which tends to pull the valve open. When the valve has been closed it is gripped by the receiver pressure acting on the back, holding it against the seat, and remains stationary during the return stroke of the piston, and also while the piston advances toward it again, until it has compressed the air in the cylinder to nearly the !ame pressure as in the receiver, at which time the pressure on the back of the valve becomes so nearly balanced that the vacuum pot can move the valve, which is then quickly thrown open. The telescopic connecting-rod is so con­structed that a small dash-pot is formed at the bottom of the tube, to avoid shock should the plunger strike the bottom while the valve is open or when the closing motion begins. It will be ob­served that no trip or releasing gear of any kind is used with these valves, the holding and releasing being done by friction, controlled in the simplest possible manner by the air pressure in receiver and cylinder. The outlet valves are also held against their seats by long fiat springs bearing in the centre on the back of the valve and at ends on blocks set in pockets at end of the valve. It will be seen from the drawings that these blocks have a clearance of! in. at the bottom, so that if for any cause the valve should be prevented from opening at the proper time, it will be only forced back from the seat, the opening of i in. being sufficient to allow the engine to run at full speed with wrist plate and vacuum pot disconnected from outlet valves. This valve gear is extremely simple, and practical tests have shown it to work admirably. 1'his engine is intended to run at a speed of 60 turns per minute if necessary.

'' In conclusion, the tendency in designing blowing engines seems to be in the following direc­t ions:

'' 1. Compounding. " 2. Obtaining valve gear which will give liberal

openings at both inlet and outlet, and which can be operated at a fairly rapid speed.

"The latter advantage can probably be best secured by the use of metal valves operated as far as possible positively, which will also do away with the vexation due to the use of leather, gum, and other short-lived materials. "

This paper received considerable discussion, Mr. F. W. Gordon, of Philadelphia, claiming that while there was no objection to the use of cross­compound blowing engines, yet their use should be confined to furnaces which can utilise the full heat of the waste gases .

Where the gases are only for furnace use, simple engines are preferable, being less expensive and with fewer parts. He cited three engines designed by him to furnish blast for two furnaces making 250 tons per day, and using 75 per cent. anthracite and 85 per cent. magnetic ores; the engines are expected to blow to 20 lb. pressure per square inch.

He preferred for blast furnaces the single to the coupled engine, and described one of his design as follows:

'~Our inlet valve is double-ported and placed inside the cylinder, whereby it works under less constant pressure and has less motion, while the increase of clearance is but one-half of 1 per cent. These valves have each 452 square inches area, which for the limited piston speed of 360 ft. is ample. The outlet valve openings in head are 6 in. in diameter, and there are 36 in all- 18 in each end. The valves are very light, of phosphor bronze, have flat seats and slide on fixed stems. The valve's centre of gravity is in the line of the seat to avoid a tendency to cant. The end of the stem is a collar 2~ in. in diameter, forming a piston fitted to a chamber in the valve. This acts as an air cushion and saves the valve seat and the noise of rapid closing. Loose leather collars, between which the air always exists, form the cushion for the opening movement. When compared to the usual area o~ air-compressor engines, these will appear excess1ve.

"Horizontal blowing engines have long since been out of date. You will note lihat our engine ~as ~ tail-end b~aring.. T.he piston rod is 7! in. 1n d1ameter, wh1eh, w1th 1ts own weight and the weight of the blast piston, has a deflection of y1a- in. The slipper referred to and the full-width bull ring of the steam piston have to carry this.

SEPT. 22, I893·]

The stuffing-boxes are made to ~ccom~odate the spring of the rod. The blast plSton 1s turned ! smaller than the cylinder, _and the b;ass ~egmen~al rings only touch the cyhnder. "e th1nk, w1th these plans well carried out,. there can ~e n o further objection to the blowing horlZont~l engine than ~o the horiz ::mtal engine so extens1 vely used, and 1t ha1 the same advantages. ''

{To be continued.)

NO TE . Tue FLASH PoiNT oF PETROLEUrtr.

IN a pa.per recently read before the _Societ~ of Chemical Industry, Mr . D . R. Steuart ra1ses obJeC­tions to the low flashing point of lamp oils, as fixed by the Government regulations. According to these, the flash point must not be below 73 deg. Fahr., as shown by the close test, but Mr. ~teuart would raise it to at least 100 deg. Fahr., whtch was the maximum flash point p ermitted under the old open test. Mr. Steuart points out that summer temperatures frequently exceed 73 deg._, and argues that under such circumstances there 1s an explo­sive mixture over the oil in the reservoir of all lamps burning low-flashing oils. Practically _all the lamp accidents have, he fin~s, occurred w1th low-flashing oils. Of twenty-e1ght lamp explo­sions examined into by Professor Abel and Mr. Red wood the flashing point in all cases was above the leaal' limit and in half the cases more than 10 deg~ above, but in ?nly ?ne case had the oil a high flash point, a~d 1n thlS case the lamp. w~s purposely designed m such a way t~at the 01l m the reservoir was h eated by conduct10n from the burner with a view to making the oil burn better.' Arguing from this, Mr. Steuart holds that the risk of explosion would be greatly reduced by the adoption of a hio-her flash test, and this is douLt­less true. It rema~s to be seen, however, if the game is worth the candle. Considering the thou· sands of lamps used, often by very ignorant and careless people, the percentage of explosions m.ust certainly be exLremely small , and to our m1nd this fact shows that the Go\·ernment requirements are in practice amply sufficient, and that no ad­equate ground has yet been shown for fur~her legis­lat ive interference with a great industry. N o case for such interference can be made out by laboratory experiments as conducted by Mr. Steuart. By means of experiments on lamps he found that _under certain conditions the temperature of the o1l may exceed the flash point, though actually this was not reached in any of his experiment~ , the outside t3mperature being low. Und er these conditions an explosive gas is given off from the sur~ace of t_he oil ; but experience seems to show that 1n practtce the explosion does not take place save under very exceptional circumstances, and hence the laboratory experiments go for nothing. If Mr. Steuart wants the ftash point raised, the proper way of going to work is by showing that these lamp accidents are much more freq uent than is generally supposed, and even then it would be a moot point as to whether the change should not be made in the lamp rather than in the oil, as there is no question but that even naphtha can be burne i saf~ly in properly constructed lamps. In all such ca'les a middle course should be steered. Absolute safety may be bought too dearly.

THE D.esiCN oF BRIDGE SuPER TRucruR.es.

E N G I N E E R I N G.

done. Nearly the same results may, h owever, be got by bracing, making the bracing between oppo­site verticals as deep as possible, and using a deep rigid connection between the floor beams and these verticals. This is as necessary near the ends of the span as elsewhere, and though with inclined end trus~es this is difficult, still it can be done by using a stiff portal overhead, and making a rigid con­nection between the inclined posts and the end floor beam. The old practice of omitting this beam and a llowing the end stringers to rest direct on the masonry was bad. In light bridges the bottom chords might easily be put in compression by over­straining the laterals, and hence in such bridges the bottom chords should be rigid for their whole length, and in other cases the end panels at least should be stiff. The practice of using a thin wall­plate of wrought iron or steel was bad, and ex­pansion rollers were often made too small in diameter. His own practice was to use in the firct place a heavy cast-iron wall-plate. Above this came a stout plate of wrought iron, to which were riveted a series of steel rails. After riveting, the tops of the rails were planed smooth and level to form a bed for the rollers. By this construction the rollers were not clogged with dust, as any that collected fell between the rails, whence it could be swept ou t periodically. The roll ers were segmental, 12 in. in diamt::ter, and spaced at 6-in. centres. Above them came a cast-steel bearing plate, and then a. rocker plate, which was a steel forging, having two cylindrical surfaces at right angles to one another, one of which took the load of the truss from the upper bearing plate fixed to the end of the truss, whilst the other transferred it to the bearing plate immediately over the rollers. This construction insured a distribution of load even if the bottom bearing plate were not quite level. \Vith respect t o the syt;tem of single triangulation, as compared with double triangulation, Mr. Morrioon hold~ that for moderate spans the former is best, as there is then no doubt as to the dis tribution of the stresses. In the case of la.rgt3 spans, however, the connections become clumsy, and the double system of triangulation i3 to be preferred. In that case the room hers of one system of triangulation can be used to stitf~n the other system. The use of curved or broken upper chords is objected to by Mr. Morrison, although it saves weight. \Vith this, only the single system of triangulation can be adopted, or the web strains become indeterminate at the points where the lines of the chord change. Tho web is very much lightened, but counters are required through nearly the whole span, and the distortion of the span is greater than when straight chords are used. As r egards cantilever bridges, they had advantages where the fixing of false work wa.s difficult or impracticable, but though the main span was lighter than an ordinary main span of the same length, this saving of weight was made up for by the additional metal required in the anchorages and outside the limits of the main span.

THE LAUNDRY E .. /HIBITION. N .\TCR.\LLY only a. small proportion of the objects

now ou \' iew at the Laundry Exhibition at the Agricul­tural Hall are of interest to engineers, but there are nevertheless several exhibits of importance, and these we propose to briefly describe. The principal no,•elty is without doubt the \Yillia.ms engine which is ex­hibited by ~Iessrs. Glover and Hobson, engineers, of St. James's-road, Old Kent-roa.d, London, .E.

In a paper to the Association of Civil Engineers, This engine is remarkable in the entire absence of C~Jrnell University, Mr. Geo. S. ~forrison, the valves, the steam distribution being effected by the designer of the Memphis Bridge, has dealt with the pistons themselves. There are two of these pistons question of bridge superstructure. American prac- mounted on a siugle rod, and working in two single­tice in bridges, he said, became established about a~ting cylinders placed opposite each other. Near fifteen years ago. Cast iron then disappeared from the middle of the piston-rocl is keyed a combined h b 'd h 1 crankpin and connecting-rod. The connecting rod is

t e rl ges, and t e practica importance of stiff- solid with the piston, and carries the crankpin, which is ness, rather than the theoretical advantage of spherical, a.t its opposi te eud. Thispinfitsintoaspheri­determinateness of the stress, was recognised. The ca.l bearing in the crank, which revolves in a closed top chords and the floor connections are accordingly chamber, arranged between the cylinders. It will be m1de now with riveted joints, and the noisy rattle, obvious that if the crank rotates under these condi­common in American bridges twenty years ago, is tions the pistons must twist in their cylinders to allow seldom heard at the present day. Plate girders are of the motion taking place, and this is what actually used up to 100 f~. or more, and may, in the future, occurs. This twisting motion brings ports formed in be adopted fur stilllon,ger spans. For longer spans the piston opposite the steam and exhaust ports of the pin-connected trusses, but very different in all other cylinder, and the steam distribution is thus effected. details from the American pin-connected bridges Diagrams show that the steam line is remarkably well of twenty years ago, are the general practice. The maintained, the cut-off sharp, and the expansion curve superstructure of such trusses sho Id b . - well formed. The ~xhaust a.!ld compressio~ lines are 1 . 1 . . u . e as corn equally good. Spec1al attent10n has been pa td to the

P ete as poss tb e In Itself. In deck bndges the two lubrication of the engines. The crank, with its pin, trusses m 1y ha br~ced togethe~ for th.e full depth I rotates in a.n oil chamber formed between the cy­of the truss, but 1n t rough bndges th1s cannot be linders, and equally efficient means are adopted for

the lubrication of the main bearings. The cylinders are lubricated in part by the splash of the oil from the oil chamber, but a. sight-feed lubricator is also _fitted on the steam pipe. \Ve Ehould add that the ptstons work without packing rings, being ground a dead t~ue fit for the cyJinders, which are reamed parallel. Owmg to the peculiar twisting motion of the pistons, the r';lb­bing surfaces soon acquire a hard black glaze which seems to entirely resist wear, and no leakage can, we are informed, be detected past the piston of a.n engine which has been a.t work four and a half years. The engine is built both simple and compound, that shown at the exhibition being of the simple type, with hori­zontal cylinders 6; in. in diameter by 4 in. stroke. \IYith 80 lb. steam pressure it indicates 16 horse­power, and with 120 lb. steam pressure 25 horse­power, the speed being 420 revolutions per minute. Though taking steam through a s team pipe 90 ft . long, containing seven bends, no thumping could be de­tected in the engine, which ran with an entire absence of noise and vibration. The space occupied by it is 3 ft. 3 in. by 3 ft. 9 in. by 2 ft. 3 in. high, and it weighs 11 cwt. \Yith a compound engine of J indicated horse-power, constructed on the same prin­ciple, it is asserted that an indicated horse-power was obtained for 30 lb. of steam, as deduced from feed measurements. A comparison of the brake and indi­cated horse-power showed a mechanical efficiency of o,·er 93 per cent. These results are certainly remark­able when the size of the engine is taken into account. The best of the engines of a. similar size tried at the Plymouth how of the Royal Agricultural Society took 42.03 lb. of water per brake horse-power, whilst others took upwards of 80 lb.

The Campbell Gas Eugine Company, of Halifax, in addition to a number of their wtll-known gas engines, show a 3 horse-power nominal oil engine of novel design. In this engine the oil (ordinary lighting oil) is contained in a reservoir fix ed slightly abo,1 e the vaporiser, to which it flows by gravity, and is there gasified. This vaporiser is heated by a lamp which also maintains the temperature of the ignition tube. The admis&ion \ralve, of the pot-lid type, is automatic in its action, opening inwards towards the cylinder as the piston of the latter makes its suction stroke. At the same time as the gas is thus drawn into the cylinder, air is also drawn in through air passages formed above the valve. On the compression stroke this valve closes, allowing the compression to take place. The exhaust va.h~e is worked by a. tappet, and the speed of the engine is regulated by arranging the governor so that when the speed exceeds its proper limit this valve is pre­vented from cloaiog. The consequence is the piston, in its suction stroke, does not create a sufficiently high vacuum to open the admission valve, and a charge is thus missed. As will be seen, this engine has neither air pump nor oil pump, and only one mecha­nically operated valve. Messrs. Crossley Brothers, of J\la.n_chester, ~xhibit two of t~H:ir_hig~·speed gas engines spec1a.lly def>Jgned for electnc hght1ng. Tbe engines run at 250 re\'olntions ptr minute, and are shown driving a couple of dynamos by means of belts. They appeared to run remarkably steadily, no s igns of flicker­ing being observable in the le.mps run from the dynamos. A third engine of their ordinary low-speed type is also exhibited.

Mei:srs. L. Hugh Bristowe and o., of Albany-build­ings, 47, Victoria-street, exhibit the Riddell patent mechanical filter. This consists essentially of a. metal receiver containing the sand by which the filtration is effected. The water to be filtered is introduced above the sand, and distributed by a number of radial arms. After passing through the sand, the filtered water flows off at the bottom into the clean \Vater pipe. The special feature about the filter is the arrangement for cleaning the sand. To this end an hydraulic cylinder is fitted above the filter, contah.ing a. piston, the rod of which passes into the filter and carries at its end a. number of radial arms. In the operation of cleaning, the supply of dirty water is cut off, an outlet from t~e filter to the sewer opened, and clean water forced 1n at the bottom of the filter where it boils up through the sand, and out to th~ sewer through the escape pipe already mentioned. At the same time the radial rods carried on the end of the piston of the hydraulic cylinder are wor&ed up and down through the sand, by admitting water pressure alternately a?ove and below the pis ton. This thoroughly shrs up the sand and greatly facilitates the cleansing of the filter.

THE EtECTRTCLIGRTAT NEw YoRK.-The net earnings of theEdison Electric Illuminating Company of New York in the first h_a.lf of this year a:mounted to 282,302 dols., as compared wtth 225,566 dol_s. m the corresponding period of 1892. and 152,~01 d~l~. tn the correspon~iing period of 1891. The number of mcandescent lamps m operation at the close of June, 1893, was 75,504, as compared with 56,704 at the close of June, 1892, and 50,615 a.t the close of June, 1891. Tbe nu m her of arc lamps in operation a.t the close of June, 1893. was 2008, as compared with 1153 a.t the close of June, 1892, and 313 at the close of June 1891. ,

370

NOTES FROM THE UNITED STATES. N Ew YoRK, September 13.

THE difficulty throughout the United States is almost entirely in the scarcity of ~urrency. Slight gains are noticeable in eastern financial centres, and money is moving somewhat mora freely in business circles. A slight incre.1.se in production is taking place, but it is unimportant. .Manufll.cturing estab­lishments are being run to fill orders only, and these are for small quantities for immediate delivery. The situation is disappointing on all sides. A vote on the Repeal Bill will probably be taken in the Senate next week. Until confidence is permanently restored, a.n improvement in business need not be expected. Scarcely any new railroad work will be undertaken this au t umn. Shipbuilding along the lakes has been generally suspended. Railroad traffic is at a low ebb. Prices for all kinds of merchandise are at the lowest point known for year3. Building operations will fall 30 per cent. below last year's throughout the country. While all these discouraging statements are correct to- day, there h a strong probability of a reaction before midwinter, as sudden and general a.s wa.s the depression in the early summer. 1'he volume of currency has considerably increased. New York banks have borrowej 42,000,000 dols. in gold from L')ndon. The coming political issue in this country is the es tablishment of a financial system which will afford a larger available supply of cur­r ency.

THE NEW ROYAL MAIL STEAMER "NlLE."

THE steamship Nile, which Messrs. James and George Thomson, Limited, Clydebank, have con­structed for the R oyal Mail Steam Packet Company's Southampton and South American mail and p~ssenger service, went on her official speed trials over the mea­sured mile in Stokes Ba.y on Tuesday of this week, and on \V ednesda.y proceeded on an eight hour.s' trial at sea, the results on both occasions exceeding ex pecta­tions. The vessel is the largest yet constructed for the company in point of tonnage, and in determining her dimensions a departure has been made from present-day pra.ctice, in respect of fast steamer3, as reguds relation of breadth to length, more from the necessity for a specified cargo capacity than from choice. The prac­tice is to increase the length of ships in proportion to their beam, with the view of obtaining higher speed while maintaining the cargo capacity, but as the vessel was intended to trade witb 'Vest India ports, as well as to Brazil and the River Plate, length was somewhat a. r estricted dimension, and it was determined to secure the required cugo space by increasing beam. In the vessels form erly built for the company-the Clyde and the Thames- the length was nine times the beam, but in the case of the Nile i t is only eight times, notwith­standing which the speed was s l.tisfactory. This gain in earning power, however, bl.s brought about another change, for the Nile is the first of the modern steamers of the company without tha t clipper bow and little bowaprit which added so much grace to our old ships and t o the early steamers. But all along the line utility is 110w the first consideration.

The overall length of the N tle is about 435 ft , and between perpendiculars 420 ft., so that she is 16ft. shorter than the Thames and Clyde, but has 2ft. more bea.m - 52 ft., and the depth moulded is 35 ft. 5 in. The gross regis ter tonnage_ is 6050 t o1s, and at 21 ft. draught the displacement u about 8000 tons. I:n her construction strength has been a first consHlera­tion. The butts of all the shell plates, instead of being fitted with butt strapJ according to the usug,l method, have b een overlapp~d and qua.druple riveted. This adds materhlly t o the rigidity of the structure. There are ten ' tb wa.rtship bulkheads, dividing the ship into eleven co:npartments, and these a re carried up to the promenaie deck, being stifi'cmed by angles connected to the fioorplates at the bottom of the ship, and to the various steel deck::~, by means of bra.cket pla tes. It is not infrequently ~·egarded as sufficient to have one or tw.> comp tmon-ways from the s tate-rooms b elow to the top-decks-one forward and one aft-which is a ll right under ordinary circumsta.nce3 · but in the event of the bulkhead d<Jors , . in the passages having to be closed, tho3e occupy10g rooms on the decks below, in intermediate comp.l.rt­ments have no eg ress to the decks abo,•e. In the Nile this c~se is met in an interesting way . Portaule gal­vanised iron ladders are bolted to the deck beams along­side of sky l ights arranged _Primarily for ventilating, and these ladders fold up agamst the deck when not re­quired but may be quickly swung down, when an easy w'a.y of escape to the deck a?ov~ is required_. The skylights insure not only venttla t10n, but a b g ht to the pl.ssa.ges. ~lost of the firs~-class _s tate-roon1s a~·e arran .,.ed riO'ht fore and aft on either s tde of the &hlp on th: mai~ and upper deck, so that each has one or two large portholes, while the . cabin bulkheads !ire fitted with ja.lousied panels . . .Right ~long t~e _botler and engine coamings are skyhghts whtch admit air and light down to the main as well as upper deck passages,

E N G I N E E R I N G.

and thence to the shte-rooms. These are sufficiently wide to afford egress to passengers to the upper deck. l•'orwa.rd and aft of these, special sky lights and fanlights are provided, so that even in the tropics a. sufficiency of air should find its way naturally into every pa rt of the ship. The stlte-rooms, which a re unusually large, being 8ft. 3 in. by 10ft., include in their equipment two folding lavatories, folding table, and two electric lights, as well as oil lamps in specially inclosed cases for emergency. The beds have all wire-wove spring ma ttresses. There is little difference between first and second class rooms, the latter being situated under the poop. Of fi r st-class passengers 215 may be accommo­dated, and of the second 36, while 350 emigrants can be carried on the main and lower decks. The navi­ga ting officers' rooms are on the promenade deck in the vicinity of the engine coarning, which is carried right above the shade deck, and the engineers ' rooms and petty officers' are on the upper deck.

The first-class saloons are forward, with the excep­tion of the smoking-room. On the promenade deck forward is the drawing or music room, plnelled in satinwood and cedar, with a chastely-designed stained glass cupola. in the centre, a.nd sumptuously furnished and upholstered. There is an upright Bechstein piano, with satinwood frame, in the forward end, having on either side beautifully ornamented music cabinets. In the centre of the saloon there is a well admitting light to the dining saloons on the upper and main decks below. This dividing of the salle-lt-manrrr into t\vo parts is common to all Royal Mu.il boli.ts; and al though it precludes the posi ibility of elaborate effort a t effect, has the advantage of economising room and insuring a more homely feeling when a small complement of passengers is concentrated in one place, for, although not frequently, it does happen that vessels a re not a.l ways crowded. In decorating the saloon the builders have very properly adopted bright wood and colours. The roof is in white relieved with gold, while the panels between the numerous port­holes on the forward end and on either side are of re­lieved scrollwork in oak on a dull gold ground, t he effect being to produce a ~ell-lighted saloon. The main saloon accommodates 107 pa<Jsengers at a large number of small tables, while in the saloon below 69 may s it, so that practically all the passengers may dine at the one hour. On the promenade deck there is, aft of the grand stairway, a ladies ' prh·ate saloon. The smoking-room is aft on the promenade deck, and is quite a cosy corner, panelled in walnut. From the room there is a companion -way to the state-rooms below, so that a passenger need not come into the open to get to any of the public rooms. The promenade deck, however, is sure to be appreciated in all weathers. The increase in the beam of the ship has increased its width, which is greater than on some of the largest Atlantic vessels ; it is 140ft. long, being divided from poop and forecastle by wells which admit to two hcvtches. The promenade is completely sheltered by the shade deck above, and t.he view seaward is unob­structed. To the shade deck has been fitted a series of electric lamps for illuminating the promenade in the evening3. The second-class passengers have the poop deck for promenade, while on it is their smoking­room, with dining-saloon below. The promenade deck being carried on T -irons above the upper deck, there is also a large promenading space on either s ide of the latter. The deck and navigtLting machinery is most complete . The cargo is all worked by hydraulic gear, six cranes and two derricks h1 ving been provided by Brown, of Edinburgh, with an hydraulic wiach for hoisting in the boats. " ' hile the davits are of the ordinary swivel type, the usual wooden chocks have been dispensed with for an effecti \'e ar­rangement by the builders, whereby the boat is released from both simultaneously by the operation of a. lever gidng a half-turn to a. fore-and-aft rod, which throws down the support of the boat. The boats all rest on the shade deck. The windlass for­ward and steering gear aft have been fitted by ~Iessrs, N a pier Brothers, Limited. The latter hag two high ­pressure cylinders, which work the ba rrel, or can be quickly connected to work the screw gear in the ev ent of the chains breaking. The valves of the steering engines are operated by an hydraulic telemotor placed in a. wheelhouse immediately under, but operated from, the bridga. Hand gear has also heen fitted aft. The light ha.s been installed by the firm 's electrical sta ff. The generating plant, situa ted on the floor of the engine- room, is in duplicate, two high-pressure engines being coupled direct t:> dynamos running a t 210 revolutions, and producing a current of lOO volts at 165 amperes. Each dynamo is sufficient t o run 320 lights. There are in the ship 500. A large cold air ~hamber has been fitted in conjunction with Hall's plant.

The engines are of the triple-expansion inverted direct -acting type, and a feature of the engine-room is the large area of floor space due to the great beam of the ship, abundant passage room being also left at the back of the engines. The machinery may be said to be Thomsen's standard type, the arrangement and details having been the result of the extensive experi-

ence of the management. The cylinders are 38 in., 60 in., and 94 in. in diameter respectiYely, with a stroke of 5 ft. 6 in., while all the working parts are of Vickers steel, including the crankshaft. The frames, bed plate, &c., are of wrought iron. The tunnel shaft is also of nu.llea.b e iron. The shafting through­out is of 19 in. diameter, and the thrust collars are of the ordinary horseshoe type. Brown's starting and reversing gear is fitted to the engines, and the air and circulating pumps are worked from the high-pressure and low-pressure crossheads. 'Veir's installation, in­cluding feed pumps, feed heaters, and e'\raporator, is fitted.

Steam at 160 lb. pressure is supplied by four double­ended boilers, 15ft. in diameter by 19 ft. long, with four furnaces in each end, making a total of 32. They have corrugated fines, and are 3 ft. 3 in. mean diameter and 6 ft. 6 in. long. The total heating sur­face is 17,300 square feet, and the grate area 650 square feet. There are three st okeholds, all with open hatchways, the boilers being arranged in pairs athwartship, each two having an upta ke and funnel. There is in the after s tokehold a donkey boiler for supplying steam for the auxiliary machinery in the ship.

The vessel is well finished , and presents a smart ap­pearance, with her two funnels and three pole masts having just enough rake. The shade deck, l'fith the boats above it, ma kes the vessel look high out of the water. She has cer tainly a high freeboard, which will tend to keep the broad promenade deck dry even in a hea\·y sea. At the trial on Tuesday, when represen­tatives of the builders and owners, with a. goodly company of guests, were on board, the sea-going qualities of the vessel were well tested, for a stiff breeze was blowing, reaching at times the \"elocity of half a gale. The measured mile at Stokes Bay '\\'as run six times, in alternate directions, and the wind was such as to interfere with the general result. Going t o the westward it was on the port bow, and in the run in the other direction it was on the star­board quarter. The mean draught of the ship was 21 ft. , the displacement being about 8000 tons. The mean of the six runs inclica ted a speed of 17.099 knots, the horse-power developed being 7200 indi­cated horse-power, the vacuum being 27 in. There was plenty of s team throughout the run. On the following day, vVednesday, with a moderate breeze, the speed on an eight hours' run was 17! knots, with the engines working under normal conditions at 83 revolutions, and developing 7700 indicated horse-power. The highest speed attained during the eight hoUl s' run was 17.69 knots. The Nile will go on her first voyage on October 19, and will be commanded by Cap­tain ~pooner. The chief engineer is :Mr. J. K. Ritchie, who has seen thirty years' service with the company, having started in the old paddle steamers working with steam at 10 lb. pressure.

CONTRACTORS AND THE ADMIRALTY. To T HE E orTon OF E~GINF.ERING.

Srn,- The excellent letter from "Sub-Contractor" in your last week's issue will, I trust, be noted by all who are engaged in carrying out Admiralty contracts. I do not know to what kind of work he specially refers, bub his remarks are certainly very applicable to ship work.

The questions of officialdom, supervision, and red tape have grown to be very serious for a contractor; and, enforcing what he says respecting supervision, there can be no doubt whatever that the Admiralty practice, whereby overseers are appointed who must personally be satisfied with a.ll details of construction, quality of materials, &c., has been latterly the cause of very unnecessary harass­ment to a. contractor.

"Sub-Contractor " says very truly that all specifications provide for everything being completed "to the satisfac­tion of the overseer. " I would, however, point out thab it is also stated all work is to be "in accordance with the usage of H er Majesty's servic~. " It is just here where the annoyance to contractors has been so intolerable. For instance, if in certain work the contractor points out that the qua.li ty of materials and workmansh_ip are superior to certain specific and similar cases in Her Majesty's dockyards, be ic; told that the work named will most likely form the subjeot of serious inquiry from bead­quarters ; on the other ha.nd, if he points out that certain details, which he is told must be carried out, are not in certain dockyard ships, it is stated the ships in question are not completed, and that the fitt ings named will be in place before they pro­ceed to sea. The contractor is thus paralysed; a.nd aa it is obvious there can be no such thing as perfection in any human handi w0rk either as regards design, quality, or workmanship, he has just to muddle along helplessly and blindly ab the caprices of, not one overseer even, but frequently quite a procession of gentlemen who succes· si vely appear on the scene at various stages of work.

But, Sir, there is another and a. more serious side to this question than that affecting the temper and pocket of a contractor, and that is the one affecting the cost and efficiency of our warships.

This is a. matter in which the general public are vitally interested. In the first place, the numberless vagaries and " fads " of overseers and other officials, although pos­sibly squeezed out of contractors for less than prime cost, will yet be not unlikely assessed and considered in future

•

SEPT. 22, 1893·] es~imates they may make. In the second place, ~re th~se vagaries and ·'fads'' really necessary to the effiCiency of ourships? . . . . . .

This ever·mcrea.smg multtphcat10n o~ watertight do.ors, valves, pipes, indicators, and mechamsm c;>f every kt.nd, is, in the opinion of many expe.rts, of b.ut ht~le practical value in time of peace; somettmes savmg a. httle manual labour, or, at oth~r t~mes, dispensing ~ith some person~l super vil:! ion; but m tu:x~e c;> f war only hkely to be .of use m creating showers of mtsstles wherever a shot s tr1kes or a. shell explodes.

Are we not really losing a grasp of broad principles in the design of ~a~s~ips, in the ~xcessi ve refinement of detail and multiphc•ty of mecbamsm?

I am, yours, &c., ' AN EYE-WITNESS.

BILBAO HARBOUR 'VORKS. To THE Eurron OI-' ENGINEERING.

StR -In your valuable journal of the 1st inst. I have read ~ communication by Mr. Waiter Robert Kinipple, M.I.C.E., in which, referring to the description of the Biluao Harbour works which you published in your number of August 25, be criticises the section adopted for the basement of the breakwater, preferring a monolithic sy~tem from the b~ttom of the sea up to the parapet.

I b~ve much re pect for the opinion of an engineer like ~Ir. Kinipple whose works on ''Concrete \Vorks under \Vater " and ~thera published in your p1per ~ ~a.ve read with great pleasure, but allow me to suggest 1t IS strange that he should criticise so hardly the section hEire adopted without having personally studied the renditions of this harbour. In these questions it is impossible to give absolute rules, for local circumstances influence very strongly the adoption of the section and mode. of constru~­tion best suited to the case one has to deal w1th.

SEA SIO~ . tiARBOUR SIDE

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L9l.ving on one side Mr. \V. R. Kinipple's comparisons of heterogeneous volumes, in which he d0es not take intv account that in the Bilbao Harbour. works t.he greater part of the volume ia formed by very mexpenst ve rubble, and that this volume and the one of the upper blocks generally conta.ins more than 30 per cent. of open space, I pass on to say:

1. 'fhat, excepb for a short distance from the coast, the bottom of Bilbao H arbour is formed by mud, so that the monolithic structure that Mr. Kinipple proposes would have no stability unless it rested on a rubble basement of at least 6 metres thickness. This gentleman must have fallen into this error on ae<'ount of the statement made in ENGINF.ERlNG of August 25 that the Bilbao Harbour is formed of sand, whereas it is formed of mud from tha levelling curve of 6 metres under low sea water.

2. That apart from the strong gale3.that have.gi.ven ~o the Bay of Biscay such a sad reputat10n, there IS 10 th1s sea, ev~n during most of the ~uii_lmer days, a constant a.~itation that renders monolithic work under low water very difficult. The concrete made ~i~h Portl.and cement is completely washed away, unless 1t 1s put mto baga, and even then it is washed on the upper part of these to a depth of 20 to 30 centimetres, that m.ust be taken off by tearing the bags. Concrete made w1th Zu· maya. cement, which is more quick setting, resists ~etter, but still it washes away a good deal. If to all these c1rcum· stances one adds that to properly set the blocks of Mr. Kinipple's monolithic structure it is necessary to employ divers, who, with the currents, movement, and generally troubled state of the sea water, work here in very bad conditions, one easily understands that very little confi· dance c1.n be put into work carried on in such conditions, apart from the consideration that the time required to carry on the work would be hard to fix, and its cost very great and difficult to estimate.

3. I must also mention that Lhe stone quarries, uoth foe rubble and concrete blocks, are on the river banks, and gi\'e plenty of very cheap stone. All this stuff is easily put in place with hopper barges during more than three hundred days of the year, so that the work goes ahead very quickly, dPspite of the great amount of material invested in it. This would not be the case with Mr. Kinipvle's system, for experience has taught us that we could not have worked to it for more than fifty d ays in the year, between April and September, so that it would be impossible to calculate the cost and the time required to do tho work.

4. The brealtwaters of Socoa and Artha, of the San .Juan de Luz H arbour, that the French Government is now building, and that have to resist the force of the sea in about the same way as the one of Bilbao, have a sec­tion very similar to my plan, which was definitely adopted for this port. The breakwater of L eixoes, near the mouth of the River Douro, recently built by the Por­tuguese G Jvernment, has also a similar section.

5. Lastly, I shall say that the eminent engineer, Sir John Coode, whose reputation cannot be slighted by any engineer, proposed for the Bilbao Harbour in 1873 a breakwater, section of which I send you, and which I should be obliged to you for publishing together with this answer, so that you may see how completely differt>nt it is from the monolithic structure proposed by Mr. Kinipple.

Sir John Coode was in Bilbao in December, 1872, studied the conditions of the place, and adopted this

E N G I N E E R I N G.

section, adding in his report : "The breakwater will consist of a rubble base surmounted by a superstructure of artificial concrete blocks, each block to contain 1000 cubic feet, or, say, 60 tons. The rubble would be depo­sited from the hopper barges .. .. The large artificial blocks will be placP.d in the work by means of a powerful steam derrick erected on a twin-screw barge, also worked by steam."*

Please excuse your old subscriber for taking so much of the valuable space of your journal, for fear of giving an incompJete Sl nswer, and b elieve me to remain,

Yours truly, EVAIUSTO DE CRURRUCA,

Chief Engineer of Bilbao Harbour \Vorks. Bilbao, September 12, 1893.

PORTLAND CEMENT. To THE EDITOR 01-' ENGINKERING.

SIR,-Will you permit me to emphasise one of the remarks in that portion of Mr. Faija's ()hicago paper printed in your last issue, as it has a. most important bearing upon the subject of testing cement, and expresses a.n opinion which I have long entertained. He says a knowledge of the material "can be~t be obtained by gauging a cement by itself, with the addition only of water, and without the addition of sand or other mate­rials, as these themselves, by variations in their composi­tion, form, and nature, introduce an element of error independ~ntly of any good or bad qualities in the cemtsnt." The late :Mr. Grant, of the M. B. W., who was mainJy responsible for the adoption of the sand test in this country, admitted to me in conversation upon the subject that be had found a difference of 50 per cent. in the results obtained from two mixtures of the same cement with what appeared the same sand. On analyl)is he found the sand which gave the lowest test had a percentage of carbonate of lime in it which could only be dected by the chemist. It is now well known that the finer the cement is ground the higher will be th e t ensile strength obtained from a. mixture with sand ; it is, therefore, only necessary to specify a neat cement test. coupled with a. given degree of fineness, and I strongly urge this method in preference to blindly follow­ing the lead of another nation which is certainly second to us in prac~ical knowledge of the subject.

I am, Sir, your obedient servant, V. DE ~IICHELE.

Higham, R ochester, September 20, 1893.

MACHINE CONSTRUCTION AND DRAWING, 1893.

To THE EorTon OI•' EscrNEERING. Sm,-In endeavouring to find some cause for the fact

that so large a number of really first-rate students failed at the late examination in the above subject, while so many second-rate students passed, I have carefully studied the elementary portion of the paper, which to some extent accounts for the occurrence.

I find there, on one of the examples, a portion marked, "Hexagonal, to fit 21-in. spanner. "

Some time ago a. correspondent of yours told us of the practical draughtsman (who had been engaged all day designing machinery of the highes t class and most modern type) crawling home to teach a science class, and so doing our professional friend out of a job.

R eturning to the examination paper, the 21-in. spanner would undoubtedly be taken by all prac-tical men to mean a. spanner that would fit a nut for a. 2i-in. bolt, say 3~ in. in the jaw. This is evidently not what was

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.. I~ ..... ,: ~~--~--~ n~a~pv~~

meant by our examiner~, as you will see by referring to Example 1, a copy of which I inclose.

The question Is, what are we to do in future ? Are we to tell our students that a 2!-in. spanner is 2~ in. in the jaw ? If so, the time has come when some one i3 re~uired at Kensington to give our examiners a little instruct10n in workshop terms.

The D epartment profess to be raising the standard of the student. I suggest that there are other standards to be raised.

September 18, 1883. SPANNERS.

ELECTRIC PO'\VER TRANSMISSION IN BELGIU.lVI.

To ·raE EDITOR oh~ E~GINRERING . Srn,-In your note las t week respecting the interesting

installation at H erstal, where the machinery in the

*The plan of breakwater proposed in this proj ect was different from the one I ha ve proposed, and which is being carried on, because then it was thought only of protecting the mouth of the river by a breakwater, and now we are making an outside harbour by means of the two break­waters that are shown on the plan in ENGINEERING of August 25.

37 1 -

Small Arms Factory is driven entirely by motors wor~ed from large dynamos, you speak of the power as ben~g furnished by a. Corliss engine of 450 horse-power. Will you allow us to say that there are t'W? engines, ~he second one which was set to work early th1s year, bemg a com­pou~d \Villans central valve condensing engine of . 300 horse-power. This engine, which runs at 35~ revol?tJOns per mmute, is coupled direct, like th~ Ccrhs~ engm~, .t<? a. dynamo of the Compagnie In~ernat10n.ale d Electr1<:1te of L !ege, by whom the whole 1nstalla.t10n was earned out.

Your obedient servants, WILLANS AND R omNSON, LrMITRD.

C. S. E s sEx, Secretary. Picton House, Thames Ditton, Surrey,

September 19, 1893.

THE SANITARY CONDITION OF LEICESTER.

T o THE EnrTOR or· ENGINEEHING. SIR,-Koowing that you h ave tal<en a.n interfst as to

the sanitary welfare of L eicester with regard to the small­pox epidemic. I beg to forward you the Leice3ter D aily .Express for Weptem her 15. by w hi eh you will see the manner in which the sanitary wmk is carried on in Leicester.

We as a town not only have been &uffering from small­pox, but also from typhoid fever, and the who1e of the latter cases have arisen within the vicinity of the J arvis­street Yard and the built-upon area adjoining the banks of the river.

When the matter was discussed before the Sanitary Committee ye terday, the chairman wa~ not present, and left the chair to be occupied by Mr. Alderman Clifton, the vice-chairman, althocgh a copy of the police report! bad been forwarded to him.

The ~uperintendent in charg~ of the nightsoil depart­ment made the startling admission to the committee that a. man had been specially engaged to do the work, which usually commenct-d at midnight and ceased at ~.30 a.m. , receiving the magnificent remuneration of 1s. 6d. per day for his services.

The Highway Committee of the corporation keep a dr6ciger almotit constantly at work to clean the lower reaches of the river and canal, and simultaneously the Sanitary Committee employ men to deposit fretid matter into the river.

Can we wonder at smallpox, cholera., or typhoid fev er epidemics whils t enlightened L eicester deals wiiih its sewage in this manner'? Yours truly,

w. H. SBIPSON. Alliance ChamberP, Horsefair-street, Leicester,

September 16, 1893.

THE NAVY. T o THE EDITOR OF ENGINEEHfNG.

Srn,-Under the beading of ''A Notable Voyage," a. paragraph appeared in most of the London paper~ of yestf'rday, in regard to the recent passage of H . M .S. l\lel pomene, which has just a.rri ved at Victoria, B . C., from Callao, having s teamed direct (5000 miles in 22 days) without making a. stop for coaling. This is com­mented on as a." noteworthy achievement, seldom paral­leled and n ever surpassed." If this is really, what it professes to be, the opinion of naval officers, the sooner they try doing something greater the better for them­selves and the service. It is 5000 miles continuous steam­ing at something under 10 knots. Not very long ago a. new Rteamer ran from Teneriffe to a New Zealand port in one stretch, and that was considered a. record for long­distan<:'e steaming. But it was quickly shown that on more than one occasion a new cargo boat has gone from the Clyde to New Zealand without slowing her engines . When merchanb ships go half round the globe-and ~o?btless co.uld go further if ~esired-without coaling, It 1s surely t1me that naval <:'rlllsers, whose raison d'~tre is to hold the sea for long periods, should not consider a trifle of 5000 miles to be worthy of prai~e or even of comment.

S eptember 21, 1893. B. w. GIN Bt!RG.

CONCRETE BEAMS. To THE EDITOR oF Elt.GINEERING.

BIR,-In your iRsue of September 15 "Student" calls my attention to the paragraph in the issue of September 1, in which you notice my experiments on the strength of concrete beams, the results of which I contributed to the Institution of Civil Engineers in a. paper appearing in vol. cxi. of the proceedings.

In my paper I explained that the discrepancy in the results obtained with the one to six concrete was due to the fact that there was insufficient fine material used in ~be ala~~ made in tbe~e. proportions to completely fill the mterst1t1al spaces. Wtth r eference to the other points your correspondent raises, L ~.hould be as be st1guests " ,. d f"l h , t" , span mstea o engt ," and the dimensi0ns of the third set of beams should be 39 in. by 18 in. by n in.

These mistakes are, of course, printer's errors. There is also evidently an error in the formula. given

for which I am not rt>~ponsible. The fi ,st factor on tb~ right· hand side of the t>quation is certainly not . 06, i b should be more nflarly. 96.

I h~d purpose<l writing to c~rrect thes-e, but pressure of busmess has prevented ruy d omg so earlier.

Yours faithfully, SIDNEY R. LOWCOCK.

35, W a.terloo street, Birmingham, ~eptember 19, 1893.

372

SURPLUS VALVE. WE illustrate below a new form of ~urplus or re·

ducing valve, made by Messrs. George Cockburn and Co., of Kinniog Park, Glasgow, and intended for use io cases in which s t eam is to be maintained a t a high uniform pressure in the boilers, whilst a part of it is used t o ~upplement or prov ide a supply to an a pparatus u~1ng steam at a lower pt e3sure. It will be Eeen f~om Fig. 1 that the piston usual in this type of valve 1~ r eplaced by a diaphragm, which C)nsist of two sheets of thin copper, suitably corrugated to obtain flexibility, and supported at the back by a number of strips of gun-metal in the shape of sector3, as

FLj.l .

A

_:..:._H. ~p- _L. P.

Pia .2. '-

. /0

shown in Fig. 2. These segments rest in a g roove formed in the valve cover, and at t heir other ends abut against a ring screwed into the valve spindle. The movement of the valve is small, being limited by a stop on the spindle, and as t he diaphragms are also thoroughly supported, they are not liable to injury from fatigue. The pressure at which the valve works is r egula t ed by the spring shown, arrangements being made by which the regulating gear can be locked, and t amper ­ing with the val ve by unauthorised persons prevented.

A USTRIAN MINERALS.- The value of the mineral produc· tion of Austria last yeo.r, not includ ing Hungary. Bosnia, and the Herzegovina, was computed at 7,04~.85 6l. In the Prizbram State silver mines, which are 1600 ft. deep, a. ne w vein has j ust been met with. It is 2ft. thick.

CATALOGUES.-W e have receivE>d from Megsrs. Bement, Miles, and Co , of Philadelphia, U. S. A. , one of the finest engineers' catalogue~ we ever sa:w. The paper, the P;rint­ing and the engravmgs are ahke perfect, and const1tute the'book a veritable edition de luxe. There are descrip­tions, mostly illustrated , of thirty·one lathes, the largest being 125 in., of five cutting-off and cantering machines, of a shaft-straightening machine, of a link hanger lathe, of th1rty planing machines, of nine shaJ?ing machines, of twel \·e slotting machines. of five milhng machines, of thirty-seven dri~li:og machi~es, of tw~nty·tbree. boring, drilling, and !Inllmg ma.chmes, of th1rteen ~ormg and turning machmes, of . four b_olt and n?t machmes, of t~n plate bending and s~ra.1ghtem.ng mac~mes, of twenty-stx punching and shearmg machmes, bestdes a large number of hydrauliC? machin~s and st~am hammers. Only large· sized machmes are mcluded m the catalogue, and often one stands for the representati v~ of a class comprising several examJ?les.- We have also received from the Water­house E lectrical Manufacturing Company, .Li~ite~, of G7, S'>uthwar k Bricige-road, L ondon, a. descr1pt1 ve h3t of the 'Vater house arc lamr.

E N G I N E E R I N G.

LAUNCHES AND TRIAL TRIPS. THE s.s. Bourbon, built by Messrs. Charles Connell and

Co.i Whiteinch, for M essrs. Hugh E vans and Co., Liver­poo , for the Liverpool and Maranham Steamship Com­pany (L imited), went on her trial trip on the 9Lh in~t. Her dimensions are : 260ft. on the water line, by 35 ft. by 22 ft., measuring about 1600 tons. Her engines, of the tri~le-compou~d type, with ~ylinders 20 in., 32 in., 54 m, by 42 m. stroke, workmg pressure 175 lb., have been made by Messrs. Dunsmuir and J a.C'kson, Go van, On the Skelmorlie mile, after a series of progressive trials, a maximum speed of about 13 knots was obtained, with an indicated horse-power of 1570.

There was launched from the shipbuilding yard of 1-Iessrs. R. Williamson and Son at Workington on Mon­day, the 11th inst ., a fine four-roasted barque, the largest yet built on the Solway. This being the hundredth vessel built by the firm she was named the Centesima. Her dimensions are as follow: L ength over all, 321. ft; Lloyd's dimensions, 296 ft. by 42 ft. by 28.5 ft. ; gross tonnage, 2961 tons; net, 2798 tons ; displacement at load line, about 6400 tons. She will carry a deadweight cargo of about 4600-tons.

L ast Saturday morning the s.s. Coquet left the Cleve­land dockyard of her builders, S ir Raylton Dixon and Co , Middlesbrough, for the customary trial of machinery and the general working of the ship. This steamer is of the well·deck type-, the principal dimensions being : L ength, 292ft. Gin. ; beam, 40ft. 6 in. ; depth moulded, 22 ft. 1 in. ; and she has a large dead weight capacity, with special arrangements for the carrying of large timber. The engines have been fitted by the North ­Eastern Marine Engineering Company, Limited, of \Vallsend-on-T yne, the cylinders being 22 in., 36 in., and 58 in. in diameter by 39 in. stroke, with two large boilers working at 160 lb. pressure. During the trials everything worked most satisfactorily, and the vesselafter ­wardd proceeded to the Tyne to load.

On the 12r h inst. Messrs. \VjJliam Gray and Co. launched at vVest Hartlepool the Bullmouth, the sixth vessel they have built for Messrs. M . Samuel and Co.'s Shell Line, of London. She is 347 ft. long by 45 ft. 6 in. beam, 28 ft. 6 in. moulded depth, and, like the other vessels, has been built to the plans and specifications of Mes3rs. Flannery, Bagga11ay, and ,J ohnson, of London and Liver· pool, for carrying oil on the outward voyage and general cargo on the homeward voyage. She is subdi vided into numerous tanks, with a total capacity for 5000 tons of oil. She will be fi tttd with a most complete ins tallation of auxiliary engine~, consisting of carg0-pumping, ballast, pumping, ventilating, and electric lighting machinery, as well as steam windlass, steering gear, and six steam winches, and a complete arrangement of cargo-lifting gear for quick discharge of gener .,.,l cargo. The engines and boilers will be ti tted by the Central 1vlarine Engine Works Company, and will be of large power, and capable of driving the ship at fully 10 knots at sea, special atten­t ion having been gi v~n to draught and ventilation in the hot climates in which she is designed to trade.

---The tri ple-screw prot€cted cruiser M inneapolis has

been launchf d for the Governn1ent of the U nited States at Messrs. Cramp's Yard, Philadelphia. Intended to serve as a "commerce debtroyer, " ~he is a st eP.l vAsseJ, r~markable alike for siz •, for speed, and for armament. The chief dimensions and particulars of her are : Length on load line, 412 ft. ; moulded beam, 58 ft. 2 in. ; mean normal draught, 23 ft .; displacement, 7550 tons; indi­cated horse-power, 21,000; extreme speed, 22 knots; coal capacity with normal draught, 750 tons ; maximum coal capacity, 2000 tons; radius of action au 10 knots, 26,240 miles ; guaranteed sea speed, 21 knots. The magazines, engine-rooms, and vitals are protected by an over-all steel deck, varying from 2! in. to 4 in. thick. One screw is immediately before the rudder, on the centre line of the ship, and is a four-bladed screw of 10 deg. more pitch than the two others, which are placed one on each quar­ter, 15 ft. forward of the middle screw and 4 ft. 6 in. above it. These are tri.Ple-bladed. Each screw has independent triple-ex paos10n vertical inverted engines. With the middle screw alone a speed of 15 knots can be attained ; with the quarter screws alone a speed of nearly 19 knots. The cylinders are 42 in., 59 in., and 92 in . in diameter, for high, intermediate, and low pressure respec­tively, and 42-in. stroke. Steam is supplied by eight main boilers, placed in four separate compartments, and carry­ing 160 lb. per square inch as their working pressure. They are double-ended, 21 ft. 3 in. long and 11 ft. 8 in. in dtameter, with eight 42·in. corrugated furnace flues, and 1128 steel 21-in. tubes. The total beating surface is 43,269 square feet, and the total gra te surface 1285 square feet. The estimated number of revolutions for extreme speed is 129 a. minute. The armament, in addition to six torpedo ejectors, is to be composed of one 8-in. 15-ton 250-pounderrifled breechloader, two 6-in. 6-ton lOO-pounder rifled breechloaders, twelve 4-in. 1.5-ton 33-pounder quick­firing, sixteen 2 24-in. 8-cwt. 6-pounder quick-firing, eight 1 46-in. 73-lb. 1-pounder quick-fi ring, and four Gatling machine guns. The 8-in. gun will be mounted as a. chaser; the 6-in. guns will be mounted one on each bow; the 4-in. guns will constitute the broadside armament. The 8-in. and 6-in. guns have heavy steel shields attached to their mountings, and in the wake of the remaining guns the ship's sides carry 4-in. and 2-in. nickel steel plates. The subdivisions of the vessel, which is furnished with a ram, are so arranged as to form a com­plete double hull below the water line.

---T he double turret ship Devastation, which has been

[SEPT. 2 2, I 893. provided with modern triple-expansion engines by Messrs. Ma.udslay, Sons, and Field, as described on page R30 ante, made a four hours' full-power trial under forced draught on Thursday, tb/~ ~4th inst. The ship was io charg~ of Commander M Kmstry, and the steaming was snpermtended by M~. Sampson, Mr. Warriner, and Mr. Charles D e Grave Sells on behalf of the contractors The Admiralty was represented by Mr. R . J. Butler th~ Steam R sser ve by Fleet Engineer Colquhoun and the Dockya.~d Steam Department by Mr. W. Rabbidge. The engmes were worked for the four hours linked up a. couple of inohes, and with a greater head of steam than they could use, as it was not deemed necessary to test them beyond the power which they were contracted to develop. ~hey wor~ed sati~factorily throughout, the vacuum bemg except10nally htgh and the revolutions of both sets of engines uniform. The cards were worked out with the following result~, from which it will be noticed that during only one half-hour did the power indicated fall below the contract :

-Revolutions.

Boiler Air Pres· Horse-Pressurt> . - Power.

Starboard. ! sure.

Port. -

lb. • In. 145 99.5 101'.0 .8 7166 H 5 99 s 100.9 .9 ? -405 1~0 100.4 100 0 .7 7029 141 103.3 9~. 7 l.l 7261l 140 103 ~ 10 I. 2 1.1 75H 135 101.5 102.5 1 15 7172 143 97 5 97.8 1.4 699J 14i l C.O. 7 101.8 1.1 7175

The above data. ga\'e the following means: Steam in boilers, 141.6 lb. ; revolutions, 100 2 and 100.7; vacuum, 28.4 in. and 28.5 in. ; indicated horse-power, starboard 3727, and 3847 port ; collective indicated horse-power, 7214 (contract power 7000). The average air pressure was 1.03 in., the maximum allowed being 2 in.; and the coal consumption, 2.11b. per indicated horse- power per hour. The speed realised, as measured by patent log, was 14. 56 knots.

On Saturday, the 16th inst., a first-class steel torpedo· boat for Her Majesty's Navy Wa9 launched from the works of Meesrs. Laird Brothers, at Birkenhead. The m.ach~nery is of the inverted triple-expansion type, a~d w1ll g1 ve great speed.

The Centurion, which was laid down at Portsmouth in March, 1891, and engined by the Greenock Foundry Com­pany, went out from Spithead on the Hlth inst. for her ?ontractors' eight ~ours' trial with natural dr$l.ught. She ts of 10,500 tons d isplacement, and forms, with her sister ship, the Barfieur, a. distinct type of first-dass battleship. Of light draught compared with most armourclads of her size, she was designed to be able to pasa through the Suez Canal wi th a. large quantity of coal on Loard, being in all other respects fully laden. H er mean load immersion is 25 ft. 6 in., and her est imated speed in this condition, under natural draught is 17 knots. Her trim on trial was 25ft. forward and 26ft. aft, so that the average draught was exactly that of her de.~igneddraught. The trial proved eminen tly satisfactory. \Vi th a boiler pressure of 14G~ Jb. and a mean of 96 revolutions the starboard engine deve­loped 4785 and the port engine 4918 horse~, or a tGtal col­lective horse-power of 9703. The contract was for 900(1. The mean air-pressure amounted to 0.18 in., and the coal consumption to 1. 9lb. J?er indicated horse· power per hour. The average speed reahsed during the eight hours' steam­ing was 17! knots by Jog.

TECHNICAL COLLEGES.-The sessions of the various technical schools and colleges !l.re about commencing. W e have received calendars from the Glasgow and West of Scotland Technical College; the Durham College of Science; U niversity College, Li verpool; University College, Nottin~ham; the City of London College, Moorfields ; and U ni versi ty College, Bri:stol, All these can be obtained from the respective registrars, the price in no case exceeding 1s. Many of them are small volumes giving accounts of the objects of the colleges, besides particulars of the curricula.

LENGTHRNING A L ARGE OcEAN STEAMER. - The North German Lloyd 's mail steamer Bayern, which has just gone out from Southampton for China has been lengt hened to the extent of 50 ft., and her tonnage increased to 5600 tons. The vessel was found too small fOl' the eastern trade, and it was decided to lE>ngthen her, and the ship was banded over to Messrs. Blobm and Voss, in Hamburg. She was placed in dry dock, and was severed amidships forward of the engine- room. The fore part was drawn forward 50 ft. by specially devised hy­draulic gear, and a complete wa.ter·tight compartment 50 ft. long built to connect the two parts, and the necessary strengthening effected. The Ba.yern is now 450 ft. long, and in the new part a main ealoon was reconstructed, the other public rooms being rearranged and enlarged. The addition to the cargo-carrying capacity is 8476 cubic feet, while a larger number of passengers may be carried. A sister ship, the Sacbsen, is now being lengthened in the same way. Of course many such lengthening operations have been carried out, the P. and 0. Company having lengthened several of their boats in recent years, while the U nion Company are having the Moor lengthened by Messrs. T homeon. Nevertheless this is another st(-)p forward of the German shipbuilders, for nothing of this nature on such a. scale has hitherto been tried.

S EPT. 22, 1893·] E N G I N E E R I N G. 373

ELECTRIC LIGHTING INSTALLATION : MEDICAL ACADEMY, ST. PETERSBURG .

•

1

Fig. s.

vJ -------.~2~------------~~ ...... __ :3 ________________________ _

r ~ ~ ' .___v_z _____ , " 3 :2 6 . 17 ~

' V I c 2,5,5 : "I I

Atm 12 , - ~ ---- --"'T'- - -~- -- - -- -- .-- - ---------- --- ----------- -------~ I I I I I I I I

I I

: : Fin . 5. I I -J I I I f I I

Tr/p/1 I

Expansion Engint

Mtd•cal

for th1 1/utri c tight station of tht lmpuiat I I I I I I I

I I I I I I I I I

Acatltmy. St Ptttrsburg .

1 b iam t" of Cyltnd Prs, 340, 550 , 850 ~"'

4

I

2

o~ September 10, 1891, on the hundredth anniver­sary of .Faraday's birthday, the foundation stone was laid at St. Petersburg of the electric light station of the Imperial Medical Academy, and exactly one year later, on eptember 10, 1892, the first electric light was supplied from this station.

The first suggestion for lighting electrically the large gathering of buildings belonging to the Imperial Medical Academy was made by Professor Egoroff. A committee was appointed, and its plans approved by the Minister of \Var. The necessary buildings were erected by the committee, and the whole installation was ordered from the firm of Pa.dolyedoff, of St. Pet eraburg.

The whole area is about 1! by l~ versts (one square mile), and the syatem chosen was high-tension, a lter­nate current, with transformers. The station is situated on the Neva, to facilitate the supply of water and coal. The greatest distance to the outer buildings is about 2000 metres (2200 yards). 'l'he losses in cables were allowed for as follows : In the primary cables, 2 per cent. ; in the secondary cables, 2 per cent. ; in dynamo and transformers, 8 per cent. ; altogether, 12 per cent. The ins tallation comprises at the present moment three water-tube boilers of theFitznerand Ga.m­per system, each of 160 square metres heating surface (1722 square feet), and 12 to 13 atmospheres working pressure ; space is left for an additional boiler. The wa.ter for condensation is taken from a well connected with the river by a 12-iu. diameter tube. The

Strokt. 40 0 "Ym

lltvolut•o ns ptr Mmult 17S .

Cyl•ndt ,. I • 116 I fP .

11 11 :&: 106 "

, Ill .. 114 .,

39 6 OP

steam from all boilers enters a large steam collector, and goes then through a. separator to each engine. The engines are vertical triple-expansion engines by Mr. F. Schichau, of Elbing, each of about 350 horse-power indicated. Two are in work at the present time, and t he foundations have been laid out for a third. Each engine is fitted with a very sensitive governor, and is coupled up directly to a large dynamo constructed by Messrs. Ganz and Co., Budapest, capable of an output of 200,000 watts with 2000 volts. The engines are of Mr.

chichau's well-known marine type, entirely with steel framing, and work exceedingly smoothly and steadily. In case of need, the exhaust may be taken to the atmo­sphere by simply shifting the exhaust valve on the condenser. The normal number of revolutions is 175 per minute, but the governor can be adjusted to give between certain limits any number of revolutions desired to suit circumstances. (See Figs. 1 and 2, page 357.)

On the same shaft with the main dynamo is coupled also a small dynamo, to give the exciting current for the larger, and this has a capacity of 180 volts and 40 amperes. All main cables are taken below the engine-room floor into the cellars, where also are rooms for the storage of oil, &c. From here they enter behind two large wooden switchboards fitted with all necessary apparatus and instruments for regulating and controlling the current. These boards (Figs. 3 and 4) are fitted on the wall of the engine-room, and well in sight of the engines and dynamos. The leads outside the

Fig. 4.

station are naked silicium bronze wires running over the top of the buildings, and protected over street­crossings with a light armature, and secured there to strong steel wires. The insulators are provided with oil filling. The main leads enter the transformers installe.d i_n well-closed boxes on t he upper st oreys of the bUildmgs, and from here the secondary leads go as usual, to the lamps. '

ome t ime ago a long and exhaustive trial was made to prove the efficiency of the engines a.ncl the mean results are given below: '

Boiler pressure . . . . . . 10 t 11 t . .. . . . o a mos, Revolutions per minute ... . .. 175 Indicated horse-power, about . . . 350 Water per indicated horse-power per

hour ... .. . ••• .. . • • •

Coals per indicated horse-power pel' bour . . . . . . . . . . . . . ..

1 kg. coals evaporated. .. . . . . .. One square metre heating surface

(10. 7 sqnare feet) evaporated abcut 8 kilos. water (17 .6 lb.).

6.08 kilog. (13.4lb.}

0. 7 kilog. (1.54 lb.)

8.8 kg. water

It may be interesting to note that similar engines have been supplied by Mr. Schichau to many other large electric light stations-for example:

Hanover . . . . . . 4 engines at 400 horse-power , . .. . . . 1 , 600 ,

Altona . . . . . . . . . 2 , 450 Bremen . .. . .. 3 , 400 Moscow ... . .. 4 , 250 St. P etersburg (among

others), for the Aca-demy of Electricity of the l\1ini3try of War . . . . . . . .. 2

K onigsberg .. . . .. 4 Zarskoe Selo . . . . . . 1 Hamburg, now in hand 3 Budapest ... . .. 2 Columbian Exhibition

&c. . . . . . . . . . 1

, , , , ,

180 120 250 800 400

1000

INDUSTRIAL NOTES.

, , ,

, ,

"

THE report of t he Labour Department of the Board of Trade enables us to take stock of the conditions of the labour market, and to compare the returns of un­employed with the returns last year at the same date. The comparison is not encouraging from a. labour trading, or commercial point of view. Laijt year th~ percentage of unemployed in January was only a little more than 4 per cent. It did not rise to more than 6 per ce.n~. till May, and f~ll to 5 per cent. in August, then nsmg to 9 per cent. 1n December. This year the proportion of unemployed in the societies reporting began with 10 per cent. in January, falling to 6 per cent. in June, and then beginning to rise to 7 per cent. in August. Now the percentage is even higher and it bids fc.ir to exceed the higher figures ere the' winter

374 E N G I N E E R I N G. [S EPT. 22, I 893.

sea9on is upon n.s. The l~rges~ p ercentage of unem· mise of an advance at a sub3equent date of another 1s. f by the boot and shoe operat ives. At a joint committee ployed ha s been 10 the ~ngmeermg and the iron and per day . of all sections of both the great unions the following stee~ trades generally. 1n a.ll the branches, the pro- T he expectation that some modus ttil•endi would be 1 programme was decided upon as instructions to be p or t ton out of work m which wag 10.7 per cent. found whereby the miners' dispute might be adjusted given to the whole of the members: I. That no man of the total: In one year only, that of 1879, was has been rudely set aside by the conclusions of the shall work more than 54 hours per week. 2. That no t hat proport10n excee.ded. Of course, the t otal out: conference held at Nottingham during the latt er part man shall work other than on the employers' premises. of work has. b een mcreased . by. the stoppage of I of last week. The ballot of the miners has been a 3. That no day-working !aster or finisher shall work th.e coal supphes, and the quest10~ 1s, To wh~t extent I remarkable one i.n some respects. The decision arrived for less than 30s. per week. 4. That no day-worker w1ll the settlement of the coal d1spute rev1ve those at wa.s "to remam firm " or in other words "starve in connection with welted work shall W<Jrk for less branches of trade ? The shipbuild ing prospects have 1 rather than surrende/" The ballot was taken on than 35s. per week. 5. That no piece-worker shall b ecome better, a:nd with increasing employment in 1 three ques tions, as follows: 1. ' Vould the men work for less than the minimum statement of wages. those bran~hes w11l come a corresponding increase in I agree t o 25 p er cent. reduction in wages or any part 6. That no direct reduGtion of wages be submitted to all .th~ sect10ns of ~a~dicraft connect~d with iron ship- thereof ? Reply : For, 226; against, 145,195; under any circumstances. The far-reaching effects of bU1ldmg. The bU1l~mg trades contmue to be busy, majority against, 144,969. 2. Would the men accept this important decision will operate all over the United o~lY. 2.6 per cent. bet.ng out of work. But the fur- the employers' offer of arbitration ? Reply: Yes, 406; Kingdom , wherever the unions have branches. " 1hether n1~h1~g trades h ave nsen from 4.6 to ~· 9 per cent., the No, 141,566; majority in the negative, 141, 160. the objects can be attained without a great strike pnntmg trades from 3.3 to 6.3, wlule the clothing 3 . • hall the men resume work where they can do so remains t o be seen. trades, _the boot and shoe tra~es, and some others are j at the old r~te. of wa:ges? Reply : Yes, 61,496 ; No, vary qutet. The cotton trade ts rather busy, but t he 92,246; maJonty agamst, 30,750. The final resolution woollen trades are slack, especially for this time of the adopted, in view of the ballot, as the final decision on year, when, usually, the winter goods are being man u- the p oints raised, said: "At the same time we are pre­fe,ctured. pared t o return to work at the old rate of wages, and we

The labour d isputes during the p~st month have not largely increased ; 59 were reported, as against 5.3 in the month previous, and 71 in June. Of the total of 59 no less than 14 are s tated to b e in the mining trades, 12 in t he textile trades, nine in the building trades, seven in t he metal trade~, four in the clothing trades, and t hree in the shipbuilding trades. The other ten were in miscellaneous industries. The aggregate number of men involved in those disputes is stated to have been 116,898, of whom no less than 113,890 were connected with mining, so that all the other disputes affected only just over iWOO. The t ables relating t o the state of trade in the chief industries show only 5 p er cent. of the members of t he engineering and cognate industries t o b e working under conditions ' ' fair" to ''very good ; '' in the boot and shoe trades only 9 p er cent. , in the furnishing trades 13 per cent., in the printing trades only 11 per cent., but in the building trades there were 48 per cent. On the other hand, t he p ercentage of member3 working under conditions of "very cl ull" to" very bad, " leaving out the intermediate conditions of "moderate'' or '' quiet ," were 67 per cent. in the eng ineering trades, 69 per cent. in t he printing trades, 54 per cent. in the boot and shoe trades, 52 p er cent. in the furnishin g trades, and only 20 per cent. in the building trades. The diminution of t he unemployed in Durham and Northumberland has been from 2.1 p er cent. to 1.1 per cent. by reason of the miners having resolved to continue working. The pauperism returns of the selected districts affected hy the coal dispute and districts affected show an increase from 297,078 t o 299,699, or from 203 per 10,000 to 205 p er 10,000. As compared with the corresponding mont h of last year, thP. increase was 17, 106, or 12 p er 10, (J00. This increase is not grea t considering the state of trade, apart f rom t he coal strike.

'£he Labou1· Ga:,t>tte continues its synopsis of the history of the coal dispute, and its official figures imply that t h e aggregat e number of persons involved was not so great as previously stated in the numerous reports published in the newspapers.

The actual condition of affairs up to the meeting of the conference of Federat ed Miners, held at Notting­ham towards the close of last week, was as follows : The Durham miners, after conferences with the coal­owners with respect t o the advance in wages proposed by the men, continued at work pending whatever might be done by subsequen t interviews or by confer­ences wit h other miners' associations. The attitude of t he Durham men was the result of a n intimation to the effect that a strike would probably be followed by a reduction instead of an advance, as the selling price of coal did not justify the latter at the present moment. ~ ince the date of that interview, however , the prices have advanced in consequence of the scarcity of coal in other d istricts, and the higher prices realised for fuel from other quarters. The attitude of the Northumberland men was even a little more deter­mined, for by t he votes of the association a levy was r efused to the federation men on strike. In both these districts the men continued at work at the reduced rates paid at the date of the dispute. In Cumberland the men were at work at the 10 per cent. advance, their further demands not being assented to. In Staffordshire a portion of the men a.re under contract ; these remained at work. In some other parts of the Midlands the men resumed work at t he old rates pending a settle~lent. In ' Vales .the strike has col­lapsed the men m most cases havmg resumed work on t he' sliding scale rates as determined at the last ~s­certainment. In the Forest of Dean a compromtse was effected while the N ottingbam conference was sittina the whole of the men to resume work on the follo v~'i'ng Monday, which they did accordingly. In the cotch coalfields the disputes generally had subsided by the date of the conference; in some districts an advance of l a. per day was granted, with the pro·

will meet the owners to discuss, in the interests of trade, the necessity of their demand being withdrawn. " This part of the resolution means that the men are willing to resume work in a body at all collieries, but not in isolated cases or in particular districts. " All or none " is the phrase used by the leaders and the men. But a pparently the principle is not to be applied severely, for there was no resolution passed condemn­ing the men who have resumed work at the old rates, and at Brierley Hill and some other collieries arrange­ments were made ere the close of last week to re-start on Monday, which was done in several instances. The twentieth r ule of the federation practically asserts " all work or none, " and even in the districts where there is most suffering the men are loyal to that prin ­ciple. But there ought to be another rule t o make the former one just. All should share whatever funds there may be in the aggregate districts, so that the suffering and privation should be equalised.

In all districts the coal dispute is in fluencing and affecting the engineering, iron and steel, and all cognate industries. In Lancashire the general condi· tion of the engineering trades may be described as moderate. There is only a slight increase as yet in the number of unemployed in any of the branches. To all appearance t he whole increase is due, not t o any further depression in t rade, but to the scarcity of fuel, a.nd t o the uncertainty which bangs over all branches of industry. The Liverpool dis trict is ad­versely affected, large nu m hers of men being out of work on both sides of the :Mersey. In the chemical working districts of t. Helens, R uncorn, and ' Vidnes the works generally are at a standstill. At Barrow-in­Furness the engineering t rades are so slack t hat quite 20 per cent. are unemployed . hipbuilding is in a very bad state; no fresh orders are coming in. The iron and steel trades are in a depressed condition, though as regards coal t hey are better off than in some other districts.

In the ' Vol verhampton district the condit ion of trade is fairly good and healthy. The mills and fur­naces are in full operation, as coal is obtainable from the adjoining collieries, at an enhanced, al. t hough not prohibit ive, price. Under ex isting circum­stances there is no anxiety t o book new orders, as prices are going up, and t he further stagnation in other districts may give a fi llip to trade where the coal dispute is not causing so much inconvenience. In nearly all branches t rade is b risk. .~ teel plates and billets are in active request, and gal vanising sheets and tin sheets are in demand. the latter on account of the limited supply from the W elsh districts. Prices in all cases are firm, in most, if not all, with an upward tendency.

In the Sheffield and Rotherham district trade is nearly at a standstill in many cases, owing to the non­supply of fuel, though at Rotherham t he pinch has not yet been felt very severely, on account of t he large stock~ which had been secured. In t his district the stove-grate, baths, a nd general joiners' and house­fittin gs trades cont inue bu~y, by reason of the actidty in t he building trades.

The miners in France and Belgium seem determined to try to bel p the British miner in his struggles and better t heir own condition at the same t ime. At one t ime it was t hought that the strike would be partial only , but matters have developed, and i t is probi:i.ble t hat the districts will declare for a general strike. It is not expected t hat the Continental strike wil l gr eatly affect the struggle in this country, but some supplies for shipping purposes have been secured already, especially for the Continental ser vioe from British ports. Some of the British rail way compa.ni~s are also getting consignments from Belgium, as the supplies are fa lling short on some of the great trunk lines.

A most important forward movement has been made

The increased activity in the labour departments of the • tat e is causing great pressure to be put upon all members of Parhament, whether or not they represent t he constit uencies affected- that is t o say, the constituencies like ' Vool wich, Enfield, Chatham, and all the dockyard centres. In this connection some searching inquiry by an independent tribunal will have to take place, or we shall drift into chaos. The men who have p ermauent and prospective advantages, above and beyond the mere rates of wages, wi11 not be able to obtain, in addition, further advances in rates of pay and reductions Cif working hours, unless those privileges are taken into account. In a private firm they have their weekly wages, for the time worked, and no more. The value of all pensions, holidays, gratuities in certain cases, sick attendance, and often sick allowance, must be taken into account. Other­wise we are simply pampering the " servants of the State" at the expense of t he t axpayer. The nation is prepared to do what is just, but there will be a reaction if more than is just is demanded.

The annual conference of the Dockers' Union held in Bris tol during the past week evinces a slight revival in the activity of that union. For the most part the proceedings were in private, the reports given to the press being officia l. Of course they were guarded in so far as the incidents of debate were concerned, though the general conclusions were made public, or t hey leaked out from time t o time by interviews with the delegates. The cash account 5howed t hat the income for the past half-year was 41 54l. 6s. 9d. ; t he expenditure was 8015l. Ss. 8d. ; so t hat the expendi· ture was nearly double the income. But the re­ported balance in hand, including the value of assets, was stated to be 3475l., besides 800l. value of goods, &c. The Recretary reported that over a million ster­ling had been added to the wages of t he dockers by the action of the union, and that a. standard of wages had been fixed, t ogether with rates for overtime. Of the total E-xpenditure, over 2299l. were expended on labour disputes in the half-year. The conference unanimously passed a resolution in favour of arbitration boards for the settlement of labour disputes. The chairman, however, intimated in his speech on the subject that the only real way was by fightin g the matter out. It is very curious that arbitration is nearly always affirmed as a principle, but very seldom applied in practice. Resolutions were also passed in favour of t he inspection of machinery, in condemnation of the use of the military in labour disputes, and some other matt ers. No official s tatement was made public as to t he actual numerical strength of the union . The most imposing parts of the conference were th e two full-dress parades, or demonstrations. The Dockers and some other bodies are always well to the front in t hese demonstrations. But the real power of a. trade union consists in organisation and financial resources, rather than in public performances where a few men can be seen and heard. Singularly enough, we seldom hear of great demonstrations in the engineers, steam· engine makers, boilermakers and iron shipbuilders, carpenters and joiners, masons, bricklayers, and a host of other well-organised trades. They are chiefly resorted to by the less organised.

THE MANU F ACTURE AND TESTING OF PORTLAND CEMENT. * (Concluded from page 346.)

T HE causes which affect the setting of a. cement are. primarily1 the proportions to ea.oh other of the materials of which 1t is COIDJ?OSed, and, secondly, the degree of their chemical a.ffimty, or in other words, the degree or manner of calcination to which they have been subjected.

In former days a very slow setting cement was sup· posed to be so, because it contained a. very large per· centage of lime. This is true on]y so far that a cement containing a large percentage of l ime will probably be slow setting, but the slow setting nature of a cement may be due to many other causes, and the most marked of these is the degree of calcination to which

* Abstract of E._aper read by Mr. Henry Faija., M.I.C.E., at the International Engineering Congress, Chica~o.

SEPT. 22, 1893·] it has been subjected. Given any combination of lim~, silica, and alumina., which falls within the limits of _a.n ordinary Portland cement compound, the degree to whtcb it is calcined will mo.ke it, within limits dependent on its composition, either a quick or a slow setting cement. The percenta.ge of a.lumina. and iron again will affect the setting of a cement to a great extent.

Independently, however, of the chemical composition a.nd calcination of a cement, there are other matters, of a purely mechanical nature, which affect the setting powers of a. cement. The age of a cement is perha.ps the most important, and there are one or two peculiarities in this; a cement when first ground may generally be gauged very eaCJily with a comparatively small quantity of water, but wh~n that cement has been in the warehouse for twenty­four hours it may be almost impossible to gauge it, as it sets or commences to set a lmost directly the water is added ; after this period, however, the cement gradually becomes slower setting, and even a very quick setting cement will in a few months become quite slow enough for all ordinary purposes.

The tensile strength of a cement is the test which is generally considered to most accurately define its value for constructive purpo~ es. A qui<:k setting cement naturally attains greater strength in a shorter period than a. slower setting one1 but a slow satting cement has probably the greater ultimate strength.

The manner of carrying out this test is to gauge briquettes in gun-metal moulds, having a. sectional area. at the smallest part of one squa.re inch ; the briquettes, a fter being left in the moulds for twenty-four hours in order to become perfectly set, are removed and placed in tanks of water, in which they are allowed to remain until they are to ba tested. The usual and most con­venient periods to test the briquettes for tensile strength, are at the expiration of three and seven days from the time of gauging. It is usual to make five briquettes to te t a.t each date, and the average strength of the five is taken as representing the tensile strength of the cement at \.hose per iods. It is also, perhaps, desirable to occa· sionally make briquettes to test at a. longer date, usually twenty-eight days, as by that means a corroboration of the opinion formed of the cement at the expiration of the seven days' test may be obtained. It is difficult to define any ha.rd and fast rule which

should govern the increase in the strength of a. cement bstween the three and seven days' test. ~Ia.ny quick setting cements will carry a. tensile strain of 400 lb. on the inch section at the expiration of three days from gauging, and will probably carry 500 lb. a.t the expiration of seven days; this would show an increase of 25 per cent., and is perhaps as much as can be expected from a cement which develops a very high tensile strength at the early date. A slow setting cement will probably at the three days' test not carry more than 300 lb. on the square inch, and perha.p" 460 lb. ail the expiration of seven days from gauging, which would represent an increa.3e in tensile strength of about 50 per <'ent. It is a lso known from experience that most slow setting cements will con ­tinue to increase in strength for a. much longer period than the quicker setting ones, and consequen tly the slower setting cements, under ordinary circumstances, will attain a. greater ulttmate strength.

It will, tb~refore, be seen that if a slow setting cement is required, it is not ad vi sable to demand, in a specifica­tion, too high a tensile strain at the early dates, and possibly 350 lb. on the square inch at the se,·en days' test 1s sufficient, whereas if a quick setting cement is required, 400 lb. is nothing too much to demand. L~tterly the author has had several specifications

before him, which, in addition to naming the minimum strength at each da.te, have also defined the maximum. T his, no doubt, has been devised with the object of securing a certain good increase in strength between the several dates at which the cement is te3ted, but such a specification defeats its own object, for whereas the best results of a cement can only be obtamed by care­ful and proper manipulation in t he testing room, a lower re3ult may be easily secured by indifferent or ca.r~less

• gaugmg. The sand test consists in gauging the cement with

three parts of sand, which should be of approved quality, sifted to a certain size and properly washed and cleansed, hub the difficulties of carrying out the test are many. Variations in the form and hardness of the grain of sand materially affect the result of the test, and the difficulties of manipulation and of making solid briquettes render it altogether an undesirable test to adopt, irrespective of which the test is a long one, the briquettes not being tested until28 days after gauging. In the author's opin ion cement should be tested by itself, not only because tho manipulation is considerably simpler, but because it is unwise to introduce into a test extraneous matters and complications which are in themselves open to consid erable variatiQn. If it is desired to ascertain the strength of a. mortar C)mpounded with any particular cement, then let the cement be gauged with those aggregates and sand which are to be uaed on the work ; by this means some definite information may be obtained as to the strength and binding power of the mortar which is to be used ; but to test a cement with what it is pleased to call a. normal or standard sand, gives practically no information in this direction, and Aimply tends to complicate and confuse an otherwise simple test .

The fineness to which a cement is ground materially affects its constructive value. Probably, if a. cement was ground to an impalpable powder the beat results would be obtained, but as it is impossible for the manufacturer to produce this degree of fineness with the machinery at his command, except at great cost, it is not desirable to d e­mand such extremely fine grinding. A cement that will all pass through & sieve having 625 holes (252) to the square inch, and which will leave a. residue of from 5 to 8 per

E N G I N E E R I N G.

cent . when sifted through a. s ieve having 2500 hole~ (502)

to the square inch, is for all practical constructional pur­poses ground fine enough.

It is now necessary to refer to the property which it is essential that all cements should possess, viz., absolute freedom from all indications of either expansion or con­traction, and that when once set it shall in no way alter its form, crack, or disintegrate.

The cracks, however, which are ~een in concrete work are not always due to the use of a "blowy cement," but may be due to constructional causes, or to the ex~ansion and contraction of the structure due to variatiOns in temperature, or to the natural contraction of the mass; and a simple crack in a. piece of concrete would hardly be indica.ti ve of a "blowy cement " unless accompanied by o~her indications, such as friability or absolute disinte­gration.

Concrete or mortar, again, may disintegrate, crack, and fall to pieces from c tber causes than the use of a '' blowy cement. " There are certain ma.tter3 often present in aggregates which, by not allowing the cement to set pro­perly, are antagonistic to the production of a sound con­crete or mortar ; the principal of these are dirt and loam, and there is no doubt in numerous instances the cement has been blamed when the real fault has been either that the aggregate with which it was used was dirtyorunsuit­able, or that the concrete or mortar had been improperly manipulated ; and a uper of cement ~hould be as careful in his choice of aggregate, sand, and water as he is in his choice of cement .

A cement may blow within a few hours of its being gauged, or it may not blow until several months after­wards. A cement may blow when it is very fresh and newly ground, and will lose that tendency a fter it has become aged. Some cements will blow whether they are new or old.

The cause of ''blowing " in a cement is genera.lly due to a n excess of lime in its composition, or to an imperfect combination of the lime with the silica and alumina. It may, however, be due to other causes, as, for instance, to the presence of other basic materia.ls unduly entering into the composition of the camen t by the use of improper raw materials. One of these, magnesia, created a con­siderable scare a few years ago. Sulphate of lime, or gypsum, is another, which, although it has nob attracted the attention of u ers like magnesia, is more of ten found in cements, and when in any considerably quantity, u n­doubtedly has a very great power of rendering a cement blowy.

Several means ha~e from time to time been devised for ascertaining, within the limits of time of an ordinary teat, whether or no a cement is absolutely sound, and that p rocess or test which was devised by the author some fourteen years ago is now in general use. The apparatus in which the teat is carried out, and the means of carry­ing out the test, are fully describPd in the Proceedings of the American Society of Civil Engineers, vol. xvii., November, 1887, in a paper which the author },ad the honour of communicating_ to that society, beaded "Port­land Cement T esting." Briefl7, it is a vessel containing water, the water being ma.intamed at an even tempera­ture of about 110 deg. to 115 deg. Fahr . ; there is a cover to the vessel, so that above the water there is a moist atmosphere which has a temperature of about 100 deg. Fahr.

The manner of carrying out the test is by making a. pat, in the manner already described, on a small piece of glass; immediately the pat is gauged it is placed on a. rack in the upper part of the vessel and is there acted upon by the warm vapour rising from the hot water; when the pat is set quite hard it is taken off the rack and put bodily into the water, which, as has already been stated, is main­tained at a temperature of from llO deg. to 115 deg. Fahr., and in the course of twenty-four hours it is taken out and examined, and if found then to be quite hard and firmly attached to the glass, the cement may at once be pro­nounced sound and perfectly safe to use; if, however, the pat has come off the glass and shows cracks or fria­bility on the edges, or is much curved on the underside, it may a.t once be decided that the cement in its present condition is not tit for U£e ; the blowing, however, may only be due to the extreme freshness of the sample, and though a. cement in its fresh condition is unfit to use, it may be a. perfectly ~ood cement when aged, and in order tha t a cement should not be condemned unjustly it is advisable in the event of a cement showing a tendency to 'blow on the first experiment, to lay some of it out in a. very thin layer on a. tray, so that it may be thoroughly cooled, and in the course of a few days another pat should be made and treated in a. similar manner ; if this pat g-oes thro\tgh the ordeal successfully and is perfectly sound, it may be fairly assumed that the cement only requires ageing to be a. perfectly useful one ; if, on the other hand, the second test proves unsatisfa.c­tory, it would not be advisable to use the cement. A cement may show indications of blowing while it is on the rack in the mois t beat of the vessel ; if this happens it is needless to say that no corroborative test ia required, the cement must be absolutely worthless.

It is hardly possible to dismiss the subject of the sound­ness of cement without reverting to a test that was sug­gested some three years ago by M. Deval, and which was reported upon by M. De Chatelaine, anci known as the "hot test." It consisted in gauging briquettes in the ordinary way, either naat or with sand, and when they were set, placing them in water whieh was kept at a temperature of 80 deg. Cent. (i.e., about 177 deg. Fahr. ), and it was main~a.ined that by so treating a briquette, the strength due to twenty­eight days, as carried out in the ordinary way, was at­ta.ined by this method in considerably less time, and thereby the constructive value of a. cement could be more quickly ascertained. h was also maintained that this

375 treatment of a cement determined whether it was a sound cement or not, for if the briquettes did not stand this excessive ternperatur~, but cracked or became soft, then it was asserted that the cement was an unsound one.

' Vhen the author devised his apparatus for determining the soundness of a cement, which has already been described, he naturally had to make a great number of experiments before deciding on a. t emperature which it was ad vi sable to adopt, and he then found that although some cements would bear being almost boiled, many cements, that were in every respect good and sound cements, would not stand the mvist a.tmos{>here and sub· s~quent warm bath if the temperature wash1gher than that which he adopt~ viz., 11G deg. Fahr. for the bath ; he there· fore, when M. JJeval's test was made public, made a long series of experiments to satisfy himself that he had made no false deduction in his previous experiments. The conclusions which he arrived at after these experiments with the "hot teat " were the following:

1. That if a cement was really blowy his own appa· ratus showed it equally with the hot test.

2. That the induration of a good cement was hast~ned as mucht and sometimes more, by immersing the bri­quettes 10 water maintained ab the comparatively low t emperature of 11G deg. Fahr., as when immersed in a bath at the enormous temperature of 177 deg. Fahr.

3. That no "fully " Hmed, as distinguished frvm "over," limed cements would withstand the "hot test, " but that all fully or over clayed cements would stand it, and that consequently the test acted prejudicially to what is accepted as a good cement, and gave preference to the over-clayed and quick setting ones.

4. That nearly a.ny cement that had been aged suffi . ciently would stand the hot test.

As the result of tbe!e experiments, the author came to the conclusion that the hot test could hardly be con· sidered a satisfactory test, and as the test has not made any great headway with either users or manufacturers, it seems that the conclusion he arrived at was fully justified .

In conclusion, the author begs to submit the following notes on samphng and cement test in~ for the considera· tion of cement users. The specificatiOn is one which he has now adopted for Eeveral years, and finds that it in every way satisfies the requirements, and insur es the de­livery of a good cement.

Sampling.-When it is required to take a sample of cement for testing, it is desirable, in order to secure a fair average sample, to take a small quantity from several out of every hundred barrels or sack$, or the ~qui valent in bulk, and mix them all well together before taking the quantity required for testing, the samples being taken well from the centre of the sacks, barrels or bulk, and not from the surface, as that portion may have been acci­dentally damaged. When sampling from fresh or new cement, it is always advisable to cool it by laying it out iu a thin layer for a few days, before putting the test in band.

Gauging and Manipulation.- T o obtain the best results, the minimum of water should in all cases be used when gauging cement. Small experimental pats should be made with a weighed quantity of cement and a. mea­sured quantity of water, in order to determine the exact amount of water required to properly gauge the particular sample under consideration. Having arrived a.t this knowledge, a. sufficient quantity of cement for filling a nest of moulds should be weighed out and the proper amount of wat&r added thereto. It should then be gaugad with a trowel to the proper consistency, and filled into the moulds, being lightly rammed and gently shaken in order to remove a.ll a.ir bubbles. The briquettes should then be smoothed off and placed on one side. The whole operation from the time of adding the water to the cement to placing the briquettes on one side should not exceed five or six minutes. The briquettes should be removed from the moulds at the expiration of twenty -four hours from gauging, and placed in water where they should remain until due for testing. It i; customary to determine the tensile strength at the dif­ferent dates by the average of five briquettes at each date.

Three pats should be made on pieces of glass or other non-porous substance, and their behaviour watched under the following conditions : Pat No. 1 may be left in the Air, a.nd No. 2 should be put in water as soon as it is set hard. Pat No. 3 should be treated in the apparatus for determining the Roundness of cement.

SPECIFICATION. No. 1. Finene~s.-To be such that the cement will pass

~brough a sieve having 625 holes (2~2) to the square mch, and lea,·e only 8 per cent. reatdue when sifted through a sieve having 2500 holes (502) to the square inch.

No. 2. Expansion or Contraction.-That a. pa.t made and submit ted to moist heat and warm water at the tempera­ture~ and in the a{>paratus alrea~y described, shall show no s1gns of expansiOn or contra.ct10n {blowing) in twenty­four hours.

No. 3. Tensile Strenoth.-Briquettes which have been gauged, treated, and tested in the prescribed manner to carry an average tensile strain, without fracture, of at least 250 lb. ~r square inch at the expiration of three days from gaugmg ; and those tested a.t t he expira.tion of seven days from gauging to show an increase of at least •

* ~f a twenty-eight days' test is required, the average tensile strength should be at least 450 lb. per square inch and it muab be noted that the increase in strength deve~ loped between the different dates is an indication of the growing strength of the cement, acd admits of an ap­proximation being formed of its ultimate strength· but 1t is impossible to lay down any bard and fast rule ~s to what the increase between the different dates should be ;

per cent. over the strength of those at three days, but to carry a.n average tensile strain of at least 350 lb. per square inch.

The strain should be applied to the briquette ab the rate of 400 lb. per minute.

THE DISPOSAL OF REFUSE.* IT was with some reluctance that I accepted the invita­

tion to read a paper upon the" Disposal of Refuse" before the members of this important Asc:~ooiation. Although anxious to add to the large store of very valuable papers read before this learned body, I felt doubtful whether the matter I should be able to produce would be sufficiently new and useful to interest 1ts members, and therefore I hope to be forgiv~n if portions of m~ remarks be con­sidered old or umml>ortant. The subJect has so often been before the pubhc in the form of papers S~nd reports given by able men, that it appears difficult to. record new and interesting matter. I also felt some dtfficulty, as being the inventor of appliances for the treatment of r~fuse, lest my remarks upon the subj~ct might appear biassed in one direction ; but as N ottmgbam can lay claim to the first man who successfully coped with the treatment of refuse, I came to the conclusion that ~ome­thing should be done to show that we bad not only mtro­duced and helped to develop modern methods, but bad kept level with the times, and, if possible, thrown further light upon this important subject.

It is, I think, generally known and acknowledged that when the late Mr. Alfred Fryer entered the field of operations some eighteen years a~o, the crude methods then in use were far from satlSfactory. Dry house refuse mixed refuse, excrementitious matter, and sewage refuse' treatment had been in the experimental stage f~r some time, bub no one had shown to the world that 1t was possible to deal. with these objectic;mable matt~rs without creating a nUlsance, and the apphances then m­traduced were only used at a very heavy cost to the rate­payers. At ~hat time the pa~l sy_stem was believed t? be the right thing by most samtanans. The CorporatiOns of Manchester, Oldbam, Rocbdale, Halifax, Nottingham, and some smaller towns, were spending enormous sums in its introduction, and there is no doubt in my mind that the pail system was then a very important advance upon the midden system. The old midden system was far different to what is called the midden system now, as formerly the authorities appeared to have no restrictions upon the size of caverns made to receive ashes and other refuse from houses, int.o which the excrementitious matter from a large number of closets was discharged. Many of these held refuse of this kind from over 100 people, accumulatin~ for two or three months, and decomposing and giving off germs ?f disease, not o~ly from deco~posi­tion1 but also from mfe)ted people, m the very mtdst of the mbabitants. At times even these dreadful dens of infection were so much overladen that the filth has been piled against the walls of human dwellings, and required repeated applications to the authorities in order to obtain removal ; the stench of this dangerous filth was beyond description, and the whole neighbourhood became sur­charged wi~h fou! air, and t~us ?elpe~ the propagation of disease, tf not 1tself producmg mfect10n.

Although most of Mr. Fryer's inventions dealt with refuse in a more divided form, as resulting from the in­troduction of the pail system, he also provided for the treatment of refuse from these foul middens. He de­vised appliances by which the. top portion of the cavern midden refuse could be burnt m a destructor furnace, and he devised a process to d~al with the slop portion, ~hich consisted of a small port10n of ashes, a large quanttty of urine with a proportionate amount of solid excrement. His a,'pparatus for dealing with the latter was similar in some respects to _apparatus be had invet;:tt~cJ for ~he evaporation of mol8ture from sugar cane Jutce, which apparatus had then been largely introduced into the West Indies, and produced a portable sugar named '' Fryer's concrete."

This machine consisted of a revolving cylinder having a central shaft, supporting plate iron volutes with several thousand feet of surface, and the liquid material was fed into these cylinders at one end, and discharged at the other by an ingenious ~rrangement of lifting po~ke_ts acting in the form of a mrcular elevator. As the hqUld containing a certain amount of solids was passing through the cylinder, a current of ~ot air, or of. tb~ products of combustion from the burmng of refuse m hts destructor, were drawn from the cylinder by means of a fan, and the moisture carried along with the current. Mr. Fryer's object was to obtain heated gases co~taining sulphurous fumes given off from the refuse1 whtch helped to fix the ammonia contained in the liqutd excrementious matter. These gases aD;d hea~ed air were very off~nsive after leaving the drymg cylinder, and, to avotd nmsance, they were led into a condenser, and afterwards to the furnane fires. The residue came out in the form of a black powder containing fine ashes and a large amount of salts of ammo­nium, phosphoric acid, insoluble phosphoric acid, and oh lo-

a slow setting cement will probably increase 50 per cent. between the three and seven days' test, and 25 per cent. between the seven and 28 days, whereas a quick setting cement may increase but very little. All cements should, however show an appreciable increase in strength between' the different dates, but as the increase in strength is not so great with q~ick setting cements. as with slow setting ones, the tensile strength of a qmok setting cement should be greater at the shorter. dates t~an a slow setting one. All cemen~s, more espe01all;r qmck setting ones, become _slower settmg and generally 1mprove in tensile strength With age.

* Abstract of paper read before the British Association at Nottingham, by Mr. Wm. Warner, A.M.I.C.E.

ENGINEERING rides of potassium and potash, which are valuable fertilisers. The change so promptly brought_about by sanitary a?tho­rities from the midden to the patl system, and agam to water carriage, together with the expense in this mode of treatment, prevented these appliances from general adoption.

Mr. Fryer, however, brought his skill t_o bear in per­fecting his other invention for dealing w1th the matter produced in systems then taking precedence, and he turned his attention to the treatment of pure excre­mentitious matter collected from pail closets, and also to the treatment of refuse collected from ash tubs, from the new style of midden (which only contained about one week's output). The middens being built above the groand level, and having only capacity t o allow of small accumulation, minus urine and rain water, the refuse may be termed "dry refuse." It has been found by experiments, that excrementitious matter, when' kept> entirely separate, will produce a very valuable manure, the price being regulated by the nitrate market. This concentrated manure is worth at the present time 6t. per ton, and those towns keeping the pail contents pure, and treating it in the best ap,Paratus, have shown a fair revenue. The towns of Birmmgham, Staf­ford, R ochdale, and Warrington have benefited to a very large extent by machinery producing concentrated manure upon the lines invented by :lVIr. Fryer. and are now sell­ing it at about Gl. per ton, against an average cost of 3l. for labour and interest on capital expended on plant. It is, however, only fair to state that the extra cost of col­lection is greater than the 3l. per ton saved in its manu­facture. It is questionable whether the concentrated manure produced at Manchester has been a source of revenue m manufacture, entirely owing to the details of pail closet arrangement, whereby certain portions of fine ashes are deposited in the pails, and thus the contents are adulterated. The principal features of Fryer's t reat­ment of crude excrementitious matter, consisted mainly of apparatus similar to that employed in large sugar fac­tories, with the addition of drying machines and de­structor furnaces to generate steam. The pail contents were discharged into a tank on the ground level, and there mixed with about 1 per cent. of sulphurous acid to fix the ammonia. Before heating, the liquid is elevated into a large store tank and conducted, by means of _pipes and valves, in small quantities, into a vacuum pan. These pans are constructed with taper bottoms, so that the thick portion may settle and pass out first. The more liquid portion in the body of the vessel is acted upon by the hot surface of a wrought-iron drum, having a large number of tubes passing throue-h it. This drum is heated by exhaust steam from the engine driving the drying machinery. The engine is also constructed with an air pump connected with the top of the vacuum pan, so that the evaporation is c0nducted by steam at low preesure, and therefore less liable to set ammonia free.

I have made many experiments with this apparatus, and have been able to evaporate over 50 per cent. of water from the pail contents in this part of the appa­ratus.

After treatment in the vacuum pans the liquid is passed into a dryer, consisting of a steam jacketed cylinder, fed with high-pressure steam from the boilers, and here about 43 per cent. of water is evaporated, with the result that a concentrated manure is produced in the form of powder, containing nearly 8 per cent. of nitrogen. The vapour given off from the dryer is also made to do duty in the vacuum pan, together with the exhaust steam. The power necessary to find steam for evaporation in the dryer and to dr1 ve the engine is produced by burning dry house refuse in destructor furnaces, and during a trial of 121 hours we were able to burn 55 tons of refuse, and :Q_roduce a useful material in the form of hard clinker. The heat produced steam to evaporate the water from over 68 tons of excreta, leaving 96 cwt. of concentrated manure. This performance is equal to about 1145 lb. per hour evaporated for 1009 lb. of refuse. This refuse was screened and of fair quality! the utmost being done to produce economical results. t will be seen from these figures that an enormous quantity of water must be evaporated to produce a good marketable concentrated manure.

Other methode are in use, as at R ochdale (where screened refuse is burnt in boiler furnaces, and the pro­ducts of combustion are passed over the liquid excreta), and also at Birmingham and Manchester, where it is treated entirely in drying machineR, but the results are not satisfactory; but all installations are generally upon the lines set out by Mr. Alfred Fryer. Although the treatment of excrementitious matter has been proved successful, the Rystem is gradually losing ground, and water carriage taking its place, even in those Lancashire and Yorkshire towns where very Jarge sums of money have been expended upon the pail system. There are still offensive matters produced from manufactories to be found in the sewers, and as the inhabitants of the better class of houses do not care to have pail closets, the sewage is foul, and requires treatment; consequently the two systems at one town are costly and objectionable. When a town is entirely upon the water carriage system, refuse is also produced in different form, and the best means of dealing with it has not yet been solved.

If we take, for instance, a town with a population equal to Nottingham, say with 220,000 inhabttants, and ~ssume that it ~as a perfect system of drainage, C'..onsist­mg of sewers with a good fall, and the latest flushing ar.rangements, with good ventilators ; the streets paved ~1th the best knGwn materials, such as ~ood in the prin­Cipal streets, and macadam on the mam roads. This to~n would then produce a large quantity of refuse, whtch may be taken at: (1) The refuse produced from sewage. about 375 tons; (2) the road refuse, about 100 tons ; (3) the house refuse, about 400 tons. The sewage

L SEPT. 2 2, I 893·

sludge, at approxima~ely_ 375 to~s pe~ day, w~~~~ consist of a nasty offensive hqUld~ ~avmg httle fertthsmg pr?· parties and being very dtfficult to handle. The sohd matter' contained in this liquid is about 37 tons, which may be ploughed into the land after the sewage water has passed through, !J-S at Nottingham, or ib J?lay be dealb with chemiCally, and then pressed mto sewage sludge cakes, and aft_erwards applie? to land. But in either case there 1s the quantity to be dealt with and its disposal is a difficult problem. The late Dr. Tidy and other eminent chemists have told us that to put it upon land in its crude form caused the pores of the land to be fi~ed by a ~in~ of solid matter, similar to paper pulp, whtch would m t1me make a ~ewage farm useless ; and there is also great ?itficulty w~en the sewage is supplemented by heavy rams, swampmg the ground where sewage farms are adopted. But if the sewage'be treated chemically, by lime, o~ the latest suc­cessful chemical known as ferrozone, supphed by the Inter­national Company, we still have the refuse sludge to deal with. It may be pressed into sludge ~akes, and these cakes may in some m stances be sold or gt ven to farmers, but generally the difficulty is not solved. At some modern works they propose to burn it along with house refuse which will still leave the mineral matter to be dealt .:Vith besides having its effect upon the efficiency of destructor' furnaces, which were first designed and in­tended for house refuse only. Schemes of this latter kind are being carried out at Hyde, Royton, and Hudders­field.

A simple method is in use at Ealing, Middlesex, de-vised by Mr. C .. J ones, the. sur~eyor,_ and appears to _do well in which the sludge 1a m1xed m crude form w1th hou~e refuse, and after draining for a time, it is led direct into his destructor furnaces. Where land can be had without prejudice to the surrounding inhabitants, there is no doubt his system has advantages, but at towns where land is limited, and objections are raised, a system of presses should be introduced to help the filtra­tiOn of water from sludge. The London County Council take their sludge out to sea in hopper steamers, and tip it into the ocean, and I understand that Salford proposes to adopt this method; whilst Glasgow, with its seaport advantages, has come to the conclusion that .sludge presses are the right things for dealing with it. The cost of dealing with sewage sludge in filter presses depends upon the chemical treatment of the sewage, and it varies from 3d. to 6d. per ton treated; therefore, with this system, a town of 220,000 inhabitants must spend over 1700l. per annum to reduce the sludge into portable form. Towns situated in agricultural districts are able to dis­pose of their sludge, after pressing, at a J>rice to cover the cost of treatment, but many towns find 1t difficult to dis­pose of. From experiments, I think sewage sludge might be made to show successful results in the manufacture of bricks, with specially designed machinery and kilns. Some of the latest schemes include arrangements for burning pressed sludge in destructor furnaces. A combination of destructors and sludge-pressing ma~hinery appears to be the most economical method of disposal up to a certain point. The towns of Hyde, R oyton, and Huddersfield have adopted these combined appliances, and at the two former places the refuse will generate sufficient steam to drive the sludge- pressing machinery. Those towns situated at the mouth of a tidal river, and seaside places, are not troubled with sewage sludge disposal, as they send it to sea with the sewage by outfallsewers.

A modern sludge-pressing plant consists of air com­pressors, with sludge-charging rams, and filter presses. 'fhe sludge is conveyed from the bottom of precipitation tanks to a large sludge well, and from there allowed to gravitate into the sludge rams. In passing forward a small amount of lime is added, in quantity according to the quality of the sludge, and to its previous chemical treatment. When a ram is charged, the compressed air produeed by the air compressor is passed into the ram, and the sludge forced vertically through pipes into the filter presses. The sludge in this state contains from 90 to 95 per cent. of moisture, and after filtering under a pressure of 100 lb. on the square inch for about 50 minutes, hard cakes are produced holding about 40 per cent. of moisture; but taking bulk for bulk, the sludge has been reduced to about one-fifth, viz., five tons of wet sludge producing one ton of sludge cakes. Considerable trouble has been experienced with this class of machinery, both in the wear and tear, and the breakag~ of press plates. The wear and t6ar is attributed to the foreign matter contained in sewage sludge, such as sand, grave], bits of string, rags, and poreions of leather and wood, causing the valves to be rapidly worn, and the pipes blocked. The breakages were also owing to the above materials collecting between the iilter plates, and thus an unequal pressure is brought upon the surfaces, sometimes of about 50 tons, thus breaking the plates. In the new appliances very few valves are used, and the wearing sur­faces are protected. The Jatest kind of sludge press has plate~ wit~ buckle~ ~ides (similar in form to buclde plates used 1_n br_tdges), gtvmg great strength. Sludge machinery of th1s kmd has recently been supplied to Wimbledon, Huddersfield, Hyde, Ha.nley, and Glasgow Sewage Work~:~.

(To be contimud. )

GA~ AT. P ARIS.-The ~even ne of the Parisian Company for L1ghtmg and Heatmg by Gas in J uly amounted to 161,494l., ascompared with 164,249l. in July 1892 show­i~g a. decrease of 2755l. this year. The aggr~gate' collec­tiOn m the firs~ seven month~ of this year was 1,698,898l. , as compared ~1th 1, 725,157l. m the corresponding period of 1892, shotTmg a decrease of 26,259l. this year or 1.52 per cent. The company is suffering, to a small' extent, from the competition of the electric light.

SEPT. 2 2, 1893·]

" ENGINEERING" ILLUSTRATED PATENT RECORD.

CO;\ll,ILEO ny W. LLOYD WISE. SELRCTED ABSTRACTS OF RECENT PUBLISHED SPECIFICATIONS

UNDER THE ACTS 1883-1888. T~e number of t'icws git•trt in the Specifi.cation Drawings is stated

t n ea.ch casr : whtre 110ne are 1nenttoned, the Specijication ;~ not tllustrated.

Jr here l _;wentions ar~ couun unicatcd .from ab,.oad, tlte N am eH J:c. , 0.1 tlte Commumcato,·t~ are gil'l')~ in italics. '

Copies of SpccijicatiQn .-: mau be obtained at the Patent Office Sal.e .Branc~, 38, Cursitor-street, Chancery-lane, E. C. ai the 1m•.{orur, prtce of 8d. '

The d~~e o.{ tl~e a;dvcrtiJJement .n.f the acceptance n.f a complete socc,.tica.tton ts, 1-n each ca.se, f}lven oft er the abstract, wuess the Patc'tl has been sealed, .when .th~ date of scaling is !Jiven.

.Any pe)·son ~nay at any ttme wttlnn two ·monthJJ jroul the date of tl~e adt·e~tUtenu•nt o.f the acceplattce o.f a complete specijicotion, 91 ce nottce at thr Patmt OJlice of opposition. to the grant of a Patent on. atty (Jf lhc grou11ds mention~d in. the .Act.

ELECTRICAL APPARATUS. 1~,.643. B . Edmunds, ~o~don~ Elect ric SWitches•

[1 ,lqg. ) October l, 1892.-Tb1S lD\'entlon relates to an electric swttcb. so .arran~e~ that when the press button is operated, the soleno1d tS energtsed to effect the operation, the current which energises the solenoid being immediately after cut off from it independently of the press button. Opposite the poles of the solenoid~ A, A'1 is a bent double-armed le\' er E, which engages

with one of the spring contact p ieces D, D~. according to which button." on" or ·• off," is depressed. The axis of t he double· armed lever is electrically connected to the supply main, so that when it is attracted by one of the magnets the circuit is completed through tt to the lamps, and when the other magnet is excited the lever will be rocked on its centre eo as to break the circuit through the lamps. The cores of the solenoids are p rovided with enlarged ends outside the coils. (.Accepted ..dtJgust 9, 1893).

2!,127. F. Ktng, London. Secondary Batteries. [5 F igs.) December 31, 1S92.-Tbis invention relates to means by which the plates of opposite denomination in a secondary battery are separated and insulated from each other otherwise than through the electroly te. The p lates B are provided with r ibs b projecting from the surface a distance slightly less than

Fig. 7.

b -,,. f'

that at which the plat~?s A, Bare to be maintained apart. At the outermost edge of each rib a piece of insulatin~t and acid res ist­ing substance is placed, and held in position against the opposing plate by the ribs, and so shaped as to deflect from the ribs any material resulting from the exfoliation of the surface of the plates or any part icles of material that may faJl C\Ut of them. (Accepted .Att!JUBt 9, 1893).

GAS, &c., ENGINES. 17,823. W. Mather , Manchester. UtUisiD.g Am·

monta, &o., for Working Engines. [1 Fi{J. J October 6, 1892.-ln this in,•ention the evaporation of the liqu id is effected in a vessel separate from that containing the stove. The \'easel is composed of a number of horizontal tubes A connected

fliLJ

at ea.oh end to beads B, B1, of which the former B itS joined at the bottom by a. pipe C with a shut·off Yalve D with the reservoir E containing the liquid anhydrous ammonia, while the head Bl is pro\ided at t he top with a. branch pipe F communi· eating with the apparatus to be supplied. The beads are coo-

E N G I N E E R I N G.

GUNS, &c. C 12,280. A . . Chamberlain, Birmingham. Cartrid ge

ases. [6 ~1g~.] July 2, 1R02 - This in,·ention relates to ~~~n~a~~r .;;,~1~tmg o~ marking c~ lindrical cart r idge cases after are fed into thel~~~n~c~re~ The cartridge case~ to be printed

f I'd . , an pass at the bottom mto the recess ~ha~t s d ~· whbcb 1S

1operated by levers from a main driven

. n veo Y pu ley fll . The picking up arrangement ~~~1~:c~~ t~·~e~n~h~f a!·dlev~r piokhs dthe cartrid~e case out of

. . . 1 e JS pus e out. Tbts arrangement cons1sts ?f a. sprmg cl,tP so arranged that when the ends touch t~e ca~tr1dge case wb1le it is ly ing in the recess of the slide t e. cltp ends open, bein.~~r pressed down by the lever aud spnng O\'er the case, encircling it and lifting it out of the

H

H

• • ' • • •

Fig . J. •

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~~..-...~ ; , 1itJ • •

rece~. q n t~e next dow.nward movement of the lever, the clip ca.rr1es w1t~ tt the <'J.l.r tndge case. The pick-up arrangement after the w1tbdrawal of the slide, places the car tridge case in ~ gap betwee.n the end. Gl of the sliding spindle G and the end of. tb~ rota~1~g maodnl D, and then the slide G advances car rying w1tb 1t a. shdmg sleeve Dl, so that tbe cart ridge ca.se is pushed on the m~ndril D. A. cylindrical type surface then comes round and pr1nts. the re~Ulred "?atter on the surface of the cartridge case. Durmg tbts operat10n tbe case is pr£:ssed up against the type surface by the roller carried by a lever operated from the dr l\'eO .shaft by a oa~. This p ressing up by the roller prevents the ma.ndrt l D from bemg sprung oft' the type surface. (.Accepted .A tL!Jtt8t 9, 1893).

MACHINE TOOLS, SBAFTING, &c. 17,567. B. E~ Newstead, Nottingham. Friction

C~u~ches. [4 Ftg8.] October 3, 1892. - Tbis invention relates to frtctton clutches. The abaft a. is fitted \\ itb a. d rum b attached to a. boss on the shaft br arms. On the other shaft c is a boss d secur~ly a~tached ~o 1t, and made with an arm to which is con­nected a nog e th1~ker at o.oe side than the other. Upon tbe boss d and on the s1de oppostte to that carry iol{ the a rm dl is a

' •• e -

•

~ .V • • • I

~ • • I I I • •

• ~ ..... · ,~ • • • •

e

l{

• ~ c Fig . 3 •

•

• ' if I •

,~,

bracket forming a ja~\' for a le,·er f and a bearing for a quick­thread~d acre'! g, wb1cb may also have a. bear ing in the boss d. T.he t~10oest stde of .the ring e is divicted, and it is thickened up to g tve ~mcreased bean ng surface for a wedge, which is tapped to form a nut for the screw g. F1tting within the jaws of the bracket d2, 9:nd firmly attached to the screw g , is a lever f con­nected by a. hnk to a. colJar capable of sliding upon the abaft c. ( Accepted .August 9, 1893).

STEAM ENGINES AND BOILERS. 19,S84. B. P. Parkes. Tipton, Stafts, and J .

M•Alpine, London. Marine, &c., Boilers. (5 Figs.] October 28, 1892.-This invention relates to Patent No. 14,844 of

1-- r --b

b -

1891, and consists io giving additional rigidity and strength to the boiler shell, &c. A corr ugated plate is bent into a. tubular shell, t he corrugations being at right an~les to its ~xis. The closing discs b or ends have also concentn c corrugattons. The

377 w~!diog edges are left plain until after the welding operation w en they are corrugated by means such M rolls. (..4 ccepted .Attyust 9, 1893J.

16,992. B. Peace and E. Adams, Sheftleld. Steam Gen.erator,.&c., Furnaces. [3 F igs. ] September 23,1892. - Tbts m veotton relat~s to furnaces for steam generatore, &c. At the baok of t~e bnd~e. a ctevice D, composed of a material ~uc~ as fi reclay, ts placed 10 a hotizontal position, and arranged 1D t e form of a box, open at the end near the hollow br idge C

Fi.g.l.

.Pig 2 • •

~ ..

c 0

it-m . • ~

and fitting t ight up to it. The underside is louned, and at the u_pper part of the end farthest from the br idge is a \'er tical opemn~ for conducting the heated air to the generated gases tr~velhng from the burning fuel lt. The device rests upon fire· bucks placed against the sides of the steam n-enerator flue and so arranged ~bat a horizontal opening is left at eaob side to ~llow the heated atr to ascend. (Accepted .Auuust 9, 1893).

17,336. R. d e Eicken , Paris. Governors for Motive Po~er En~in~s. [4Figs.) September 28, 1892.- Tbe object of th1s m vent10n 18 to pro\ ide means for stopping the eo~rine whe~ t he ~onnection between it and the governor breaks. The verttca~ ax1s et. of the governor turns in a. frame b secured upon ~be cyhn~er c. The sleeve et. operates~ by a small rocking lever e and ~otermedta.te ro~s, ~ va~ve tncluded m t he ~team admission pipe e3 m front of the dtstnbut10g box. The ver t1cal axis a is rotattd by a belt j, which connects the pulley keyed upon tbe drivin~ shaft o to the pulley h fixed upon a shaft hl which turns in a long

Pig.Z .

Fi1).3 .

sleeve b formed on the frame of the governor. The frame b carries a fixed axis i upon which is loosely mounted a rocking lever having a forked arm which embraces the abaft a below the slee,·e d .an? a abort arm m carrying a roller p made to move witb little fr1ct~on upon t~e b.eltf. The rocking lever is also pro\'ided with ~ we1ght !!i, wh1oh 10 tbe normal operation does not tend to t urn 1t. A stop r, fixed to the frame of the governor, limits t he upward movement of the roller, as it forms an abutment for the arm l of the r ocking lever, this arm being sufficiently heavy for balancing the lever m, to a g reat extent. (.Accepted .August 9 189~. '

15,677. Hon. C. A. Parsons, N ewcastle-on-Tyne. Governing of Steam Engines Turbines, &c. [2 ~·igs.J

eptember 1, 1893.-This invent ion relates to a l{overnor fo r con­t rolling the supply of motive fluid to a steam engine, in which a steam control \'alve is operat ed by a steam relay arrangement the relay valve being subject to two motions, one of which causes the constant reciprocation of the relay valve, and consequently the control ' ' a.lve, while the other varies the position of the former

IS,fn

. ' . ...

Fig. I . < I !

according to the position of the go,·erning de\'ice, and deter· mines the proportion of each reciprocation during which steam is admitted to or cut off from the engine-. The supply and out-off valve is operated by steam pressure on a. piston 8' , and its per iodic opening and closing are produced by the action of a reciprocating lever 0 which is compounded with a governor lever E controlled by an electrical or mechanical governor. (.Accepted .August 2, 1893).

IIISCELLANEOUS. SU 76. 0. Schnelle, Berlin, Germany. Sieves. [5

Figs. ] February 1, 1 93.- Tbis invention relates to sieves and means for agitating them. a is the a>.le of suspension of the shaking machine, b the sifting apparatus, c t he bearing d isc for the orank which is turned by the d riving pulley d. In t he apparatus b the single sieves are arranged abo,•e one another ,

each ha"i"l( a funnP.l fo r r~ceiving those parts which do not plss I hrou~h t he. me.shes. m 1s the bJ.~ for supplying the sifting material, wblCb IS capable of followm rr the c ircular movements of the ~achine. n is the ~ag for leadmg of the sorted material. T he ta1h ngs are collected 1n t he chests e (Fig. 1) a rranged before the sieves and .connected with t hem by channels. The lower end of the. axle al IS su.rrou~~fd by a ball piece arrangt>d in a corrc· Epo 1d1rg ball beanng a·•. The block of lead o in the disc c acts

Ptgl I

Pi.g 4 .

rtg.z.

&Sa. ~ounterwei~bt to prevent jer ks. A susp ended beal'ing f is prov.Ided conta.ming the socket of a ball bearing f ' ; this socket rece1ves the ~all piece h with a. pivot z screwed in it, and fi r mly connected w1th the ring r, the lower pivot of which is secured ~o the a?<le by means of a nut. Means a re provided for prevent· mg turmng of the sifting apparatus a round its own longitudinal axis. (~ccepted August 9, 1S93).

14,130. T. Singleton, Darwen, Lancs. Power Looms. [3 Fi{Js.J August 5, IS92.-This invention relates to msao.s for operating and controlling the brake of looms for w~avmg, the object being to facilitate the application to and Wi thdrawal of the brake from the brake wheel. An inclined slotted lever S is mounted loosely on the bracket 1 fixed to the underside of the shuttle r eet 2 at the end of the loom lever 3, and its end is conoeoted to near the end of the brake lever 5. On the connecting-rod 4 is an open spiral spring 6, placed above which is t he.adjustable fixed boss 7 fo r regulating the pressure of the spnog 6. Below the spring and loose on the connecting. rod 4 is a boss S, whi<.'h rests on the top side of the b rake le,·er 5, and on the rod 4, which passes loosely through a bole in the brake lever 5, and below the brake lever 5, is the fixed boss Sa. Fixed to the stop handle 9 is a pin 10, which is r eceived in the slot in the slotted lever 3. Below the brake lever 5 and free to move on a fulcrum stud 11 fixed to the end frame 12 of the loom is the drop catch 13, which, when in position ( Fig. 2) , allows free play to the b rake lever 5, but if it is d esired to r emove the brake from the

Fig.l Pi-g. 2.

3 I

b rake wbeell4, the operative presses on the end 15 of t he d rop c<\tcb 13, turn in~ the latter on its fulcrum stud 11, and so br ing· ing the part 16 of the drop catch to bear against the underside of the brake lever, the end of the brake lever 5 being thus slightly r aised, the spiral spring comprtssed, and the brake 17 held clear of the b rake wheell4 until tbe drop catch 13 is moved by the operative to the position (Fig. 2). Wben the loom is to be stopped by the spr ing h andle 9 being "knocked" off, the handle carries t he pin 10 to the higher end of the slot in the slotted lever 3, which is forced downwards, and by the fixed boss 7 the spiral spring 6 is compressed, and bears on the boss S a.nd on the end of the b rake lever 5, and by the latter turning on its fulcrum stud the brake 17 is applied to the brake-wheel 14, and the motion of the loom arrested without any rebound. When the stop or spring handle 9 is moved to restart the loom, the pin 10 t ravels to the lower end of t he slot in the lever 3 and raises the spiral spring and th e connecting-rod 4, and by the fixed boss Sa the end of the brake lever 5 is also raised, and the brake removed from the brake wh eel. (Accepted ~U{!tUJt 9, 1S93).

4329. w. Ackroyd, Gomersal, T. B. Ackroyd and s. Ralstrick, Blrkenshaw, Yorks. Supporting Rollers of carding Engines. [ 4 Figs. 1 February 28, 1893.-Tbis invention r elates to mounting the .. stripping" and working rolle rs by arranging the supporting journals so that, should any t hick substance enter the machine, it will be a llowed to pass forward without danger of breaking the supporting

n I

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brackets, &c. The bot tom part of t~e SUJ!p.or ting braoket A is supplied with a detachable cap B held .m pos1~1on by a set screw C. The roller spindle D r ests and r~tates 10 the JOUr~al E.' and above it is a plate secured to a spmdle, rou!ld .which IS placed a spiral spring H to allow. further co~press.JOn 1f necessary. Each side of the carding engme. is pro.'·1ded. w1th a bracket A for sup· portlng the roller K, which 1s r e tamed m the journals so long as

E N G I N E E R I N G. [SEPT. 2 2 , I 893-n.othin.g h~rd pass~s between it and the one rotating in conncc· t10n wr~th 1t, but 1f any strain takes place the spiral spring H will yield and allow the bard substance to pass. (Accepted A t,gubt 2, 1S93).

and between t.hem the ft~nged roller F, covered with material such as cloth, IS ~ou!lted 10 bearjngs formed at the bottom of the sl?t~ J . Th.e cyhndnca l measunng roller 0 is mounted in the shdlllg beanngs H fi~ted ia the parallel slots J, anci rests upon the roller F. The yarn passes between the rollers F and G and on to the mill so that it pa:-tly encircles the c lotb-co,·t>red roller F and thereby .prevents a~y p ossibility of yarn slippiof' betwee~ the rolle!s w~tbout turmng theu~. The roller G measures uactly a too~ 10 Circumference, and 1ts a r bour 1{ carrifs a pinion L en· ~ragmg a. wheel .M three times its size mounted on t he primary shaft of a" llartt ing " countn 0 carried by the bracket N secured to the standard E ; the coun ~er thus recorda in yards 1 he lengl h < f the yarn passed on to t he m1ll B. The beaming motion is dr i\ < n fro~ tht> pinion shaft P , w~icb is operated by the pulley Q keytd on 1t. A loose pulley R IS placed nex t to <~. and on a elee,·e lo -sely mounted upon the shaft P is secured the pullf'y S. A second pulley fixed oo the sleeve is connect< d by tbe belt U to th~ beaming mechanism V mounted on the framework Al. To ~nve the beaming motion the dri ving belt of the warping m<.t:on IS transferred from the pulley Q over the loose pullf'S R on to the pullt:y S. (Accepted ~ ugust 2, 1S93).

14,970. A. McDougall. Duluth, St. Louis, Minne· sota:. U.S.A. Ships for Transpol'ting RaUway Cars. [S F'lfls. 1 August 19, 1S92.- This in ,·eotion relatt>s to vessels known as " whale backs." The hull is made of steel plates secured to t rans,•erse beams, and the sides are panllel lon~itu­dinally and ,·er tioally, the top curved, the bottom roundfd, the bow macte spoon·sbapfd, and the stern skt>ged. Tbe stern is lower than th~ bow, a?d the sides and top of the boat a re abruptly ended some dtstance 10 advance, so t hat a fiat entrance is formed ma.r the etern of the boat throuAh which the <ars pass in entH·

Fig. J.

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ing the hull, and at the stern is a platform on which the cars run before passing through the entrance. The deck bulges slightly upwards at its rear, and the inner deck extends to the extreme stern end of t he boat and is firmly supported by frames. I n load· ing the boat, it is backed into a slip so t hat the t racks at the ~tern coincide with those of the deck . The. cars a re then passed 1nto the boat, these t ra<:ks on the stern bem~ capable of being broug~t up or .down to a levt>l with the tracks of the dock, by pumpmg water m to or out of the tanks beneath the false bottom. (Accepted Auuust 2, 1S93).

17,233. A. C. Moore, Anerley, Surrey, and G. Bra~don, Deptford, Kent. Wire Netting Machines. [1 Fig. ] September 27, 1892. - In th is invention, in place of the t~bes ~onta10ing belically wound wires, bobbins are provided \~l~h wnes WO\~nd ex~ernally on t hem, these being- exposed and ns1ble. The wae W 1s wound on t he bobbin B. On each side is moun ted a rolier R, O\•er which the wire pa~ses on its way to meet

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the other wire, and entwines itself with it. The bobbins occupy at the same time with it the positions A, and after several revolutions to entwine they are a ll moved to intermediate posi· tions a, to form t he entwinements t , as the tubes now em· ployed in these looms. For facilitating the removal of an empty bobbin, the spindleS can be pressed down in opposition to a spring C and can then be removed a long- with the bobbin from between the rollers R. ( .Accepted ~ugust 2, 1S93).

16,764. G. W. Lightowler and w. Kelghley, Brad­ford. Yarn Warping, &c., Machines. [3 F igs.] September 20, 1S92.-This invention relates to wa.rpingmil1s, &c., and its p rimary object is to provide means for indicating- the length of yarn wound upon the mill. A pair of measuring rollers :n e mounted upon the tra,·elling carriage, and between them the

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warp is passed as it ie fed on to the mill. Tb e rollers are operated by the yarn passin,R" between them, and acquire the sa1ne peri· pheral speed as the speed of the ya rn, tbe arbour of one of them being arranged to operate a counting apparatus adapted to Indi­cate in yards t he peripheral motion of the cylinder, and conse. quently indioate the number of yards of warp passed on to the mill. Ou the carriage D a pair of standards E and El are fixed,

17,326. W. Mather, Manchester, and J. Christie Alexandria, Dumbartonehire. Banging Webs 1~ Chamb~r~ for .steaming, &c. [4 lt i J8.] September 28, 1S92.-~hli In \'eDti~D r elates to means. whereby continuous webs of fabn c a r.e bung 10 folds or loops m cham bers ira order to lJe steameti, dned, &c. A number of spars of wood with metal ends A' forming rounded teeth and having roller s mounted in them are a:rraoge~ to t ravel parallel to each other aloof,! bearers B sup~ port10g their ends. Each of the bpars carries a fold of the web a l.oop C of wb!ch bangs down freely between each pair, the pai; be10g- kept a little apart by p rojectin.r cheeks at each end. All the spars a re strung on a pair of ropes D passing through boles in the. end fittings A 1, and longe r by seYeral fee t tba.o tbe length occ~pied . by .the spars wh~n they ~ie all as closely togt>t her as their proJectmg cheeks WJll perm1t. E :wb spar is in turn ad·

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vanced in to the chamber, b~ing. carried for ward several feet by a worm E a rranged at each Side, 10 the threads of which the ends A' of eaob engage as it is d rawn within r each of the thread by the &dvance of ~be pre~eding one. There is thus left between each two a space 10to wb1cb a loop of t he web is delivered from rollers F ab?ve,. so. that it hangs dow~ as a wid e loop 0 1• When the next spar 1s Similarly ad,·anced, th1s loop 0 1 is na rrowed and a suc­ceeding wide loop .is formed like Cl and then narrowed, the advance of each sp~r pushmg ~nwa.rds by the width of a narrowed loop C all those 10 front of 1t, and, by the pull of the ropes dra\\ing onwards all those behind it. For removing the web 'trom the chamber , the movements of the mechanism a re reversed the web being drawn by the rollt:rs F as loop after loop is wid'ened out by retreat of the succefsive spars. The roll ers Fare drh·en by straps from a shaft G connected by bevel and speed·reducing gear H to the "orms E. ( ~ ccepted A uow;t 2, US93).

17_,564. J. C. Stewart, Glasgow, Scotland. Valves. [4 F'tgs.] October 3, 18g2.- This invention relates to ,·aJ"es atd ~!lsi sts of. a spindle bat one end of which is a pad a which 'rfsts 10 1ts seat m the ~·ah•e ca.sing, and is held in position by means of a perforated d1sc c wh1<.'h compreeses a spiral epring f on the

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spindle .. In tb~ ce.ntre of the spindle ''here the pad is fixed is a bole m to wbtcb lS screwed a pin secured in the inside of a cap, .which, with a s~re'~· locks the \'al••e, aots as a dust protector, a~d 1s a push for adJUBtmg the pressure exerted within the con te.10er . (Accepted .Att,gttst 9, 1S93).

UNITED STATES PAT.ENTS AND PATENT PRAOTIOE. J?escriptions with illu~trations of in ventions patented in the

U111ted States of Amenca. from 1847 to the present time and reports of trials of patent law cases in the United States m'a.y be consulted, gratis, at the offices oi E NOINBERINO, 36 and 36 Bed ford-street, Strand. '

I VORY JJ'RO~t •rwc CoNco.- The exports of ivory from the Congo are largely increasing. In 1887 thase exports amounted to 40,009 tons; in 1888, to 55,000 tons; in 1889, to 114,000 tons; 1n 1890, to 181,000 tons; in 1891, to 142,000 tons; and last year, to 209 000 tons. Sheffield imports large quantities of African i~ory for cutlery pur· poses.