148 CURRENT TOPICS. [J. F. I.

addition of certain olefin polysulfides. With the aid of these sul- fides, sulfur cement can be made resistant to deterioration by fluctuating temperatures and can also be produced in varying degrees of plasticity. Such cements can be applied as bonding agents or as protective coatings in structures subjected to acids or corrosive solutions.

The Stevens Family.-To read of the activities of scientific men of the past, when handicaps to accomplishmen’t were almost insurmountable, fills one with wonderment. In its early history our country was fortunate indeed, in having men of wealth, educa- tion and foresightedness, who had the ability to overcome many obstacles and lay the foundations for the enjoyment of future generations. In Stevens Indicator for May, 1935, Dean Franklin DeRonde Furman of the Stevens Institute of Technology, narrates an interesting account of the third John Stevens. Known as Colonel Stevens, he was born in 1749, and came to Hoboken, N. J., in 1783. Probably the most spectacular of his activities began in 1804, when he had built a steam screw boat, the “Little Juliana,” with the first screw propeller and operated it between the Battery in New York and Hoboken. About 1805 he proposed a bridge from Hoboken to the Upper Battery. In 1816 he proposed the laying of a vehicular tunnel, not under, but in the beds of the Hudson and East Rivers, and drew plans to show how it could be done. His newly built steamboat “Phoenix,” in 1809, was the first steamboat to ply the open sea. Beginning with the year 1813, Colonel Stevens and his sons Robert L. and Edwin A., the latter founder of the College, contributed much toward naval construction. The work of Colonel Stevens, relating to the early development of railroads, is well known. In 1851 John Cox Stevens, another son, as commander of the yacht “America,” won the famous “America cup ” which, despite many efforts of English yachtsmen, has remained continuously in this countrv to the present day. In the present day of specialization, we are liable to forget the versatility of the founders of our country. R. H. 0.

Dust Storms in Other Lands.-According to the United States Weather Bureau, this country does not have a monopoly upon dust storms-far from it. One of the most remarkable dust falls in history resulted from a great storm which raged over the dry steppes of southern Ukraine in 1928, blowing up such dense clouds of dust that day was turned into night. It was estimated that 15,4oo,coo,ooo tons of earth were swept up from the soil.

In March 1901 heavy dust storms occurred in the deserts of

July, 193j.3 CURRENT TOPICS. I49

southern Algeria. A cyclonic storm sucked up dust and deposited it over an area extending as far as 2,500 miles from the place of origin. In 1902 a dust storm swept nearly the whole of Australia and the surrounding ocean as far away as New Zealand. At many inland towns the darkness produced almost equaled that of the blackest night and in the houses nothing could be done without lamps or other means of lighting. Added to this were some phe- nomena of an even more terrifying character. At Boort and in some parts of the Riverina the storm was accompanied by a sort of globular lightning and “fireballs” were seen falling on the fields and roads.-Electrical displays in the form of brush discharges (St. Elmo’s fire) are not uncommon in connection with our American dust storms. c‘.

A New Air Filter.-A well-known radiator manufacturing con- cern has announced a new corrugated fiber board air filter, of the replacement type especially designed to give uniform resistance and efficiency, thus reducing power costs in air conditioning appa- ratus. The filter is composed of two wafers of the corrugated fiber board placed together so that the cellular passages in the two boards, which are cut at a 45” angle, form a V-shaped passage with a 90” angle in it. These angles cause the air flow to change direction twice and scrub along the sides of the passages.

The entire filter is coated with a special compound that saturates dust, catching it in the filter. Each dust particle as it is saturated becomes a medium for catching other dust thus insuring long life for the filter. The coating will not become rancid, remains tacky at - IO’ F. and will not drip at 180’ F. Three models of the filter are offered, each one especially fitted to a certain type of condition- ing unit. The difference lies in the diameters of the air passages.

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A LOW Melting Alloy.-At a recent convention of the American Chemical Society, SIDNEY J. FRENCH described a new quinternary eutectic of bismuth (41 per cent.), lead (22.1 per cent.), tin (10.6 per cent.), cadmium (8.2 per cent.) and indium (18.1 per cent.). This alloy melts at 116.4’ F. and freezes at 116.0” F. The cost of the alloy at the present price of indium will range from $2.50 to $5.00 per ounce. The additions of small amounts of mercury or thallium will lower the melting point still further. An alloy composed of the first four metals of the five just listed has been known variously as Lipowitz Alloy or Wood’s Metal. Its melting point is somewhat higher than the indium-containing counterpart, it being 161.0’ F. C.