April 15, 1932 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 223

EFFECT OF HIGH CONCENTRATIONS In concentrations of sulfite waste liquor exceeding 1000

parts per million, the values obtained are more marked and a wider range of determinations becomes available. In Table VI1 are given values determined by Standard Methods of Analysis, with the exception that oxygen consumed was made in accordance with the proposed modification. The B. 0. D. was determined a t 25” C. Oxidation with bromine was used for the determination of sulfates. The dilutions of the sulfite waste liquor in stabilized sea water (blank) were prepared with a micropipet. The results are the average of three dilution sets.

In Figure 3 these values are plotted on a semi-logarithmic scale and show the same general effect with increasing con- centration. By comparing such values with .&milar values obtained from unpolluted sea water in the same locality, it is evident that a measure of the extent of pollution may be obtained. TABLB VII. ANALYTICAL VALUES OF VARIOUS CONCENTRA-

TIONS OF SULFITE WASTE LIQUOR IN STABILIZED SEA WATER DIQEST’ER COLOR LIQUOR I N DISSOLVED & D A Y OXYGEN RATIO PT.CO

SEA WATER OXYOEN B. 0. D. CONSUMED SULFATES S04:Cl STANDARD Parts Ma./!iter Mg./liter Mg./Ziter Mg./Ziter . . 10,000 -34.3 387 8,000 -28.5 304 6,000 -24.0 169 4000 -12.2 149 2:ooo 0.75 72.5

1,000 3.90 32.9 800 4.00 28.6 600 4.90 21.9 400 5.87 14.5 200 5.95 7 .8

100 6.55 3.7 80 6.70 3.1 40 6.80 1.9 25 6.96 0.8

Blank 7.10 0.0

1295 0.2791 0.1654 112 770 0.2697 0.1598 92 635 0.2613 0.1549 76 551 0.2551 0.1512 46 219 0.2461 0.1459 25

106 0.2400 0.1426 8 83.3 0.2413 0.1429 7 62.2 0.2398 0.1421 5 43.8 0.2393 0.1406 5 20.3 0.2362 0.1400 4

14.1 0.2363 0.1397 4 12.1 0.2367 0.1403 3 7.25 0.2369 0.1404 3 7.45 0.2372 0.1405 2 3.8 0.2381 0.1406 0

APPLICATION OF RESULTS TO FIELD MEASUREMENTS The analytical values reported were obtained on dilutions

of sulfite waste liquor in stabilized sea water. They represent

an order of magnitude rather than the correlation of sea water with sulfite waste liquor. Both of these are too variable to permit of quantitative relationships. Nevertheless, the values may be taken as approximations of sulfite waste liquor pres- ent, as is obvious from the following table:

SAMPLE 1. Puget Sound surface 2. Puget Sound: 40-ft. depth 3. Inland Bay surface 4. Inland B a i 18-ft. depth 5. Near dispoAal sewer of sulfite

8. 1000 parts sulfite waste per mill

&DAY OXYGEN PH COLOR B.O.D. CONSUMED 8.1 8 . 1 8 .1 8.2

7.1

13 14 12 13

90

1.62 0.83 1.35 1.14

30.15

2.15 2.24 2.38 1.94

177.6

million parts of sea water (sample 3) 7.2 33 27.1 96.6

By consulting Table VlI, the quantity of sulfite waste liquor in sample 5 ranges from 900 to 1500 parts per million, except that the color is much higher than the color scale of the stabilized sea water for such concentration.

LITERATURE CITED (1) Benson, Paper Trade J., 90, No. 24, 69 (1929). (2) Benson and Hicks, IND. ENQ. CHEX., Anal. Ed. , 3, 30 (1931). (3) Bruce, Brit. J. Erptl. Biol., 2, 57-64 (1924). (4) Crocker, J. IND. ENG. CHEM., 13, 625 (1921). (5) Irvine, J. Biol. Chem., 63, 767-81 (1925). (6) McClendon, Ibid., 30, 274 (1917). (7) Oregon State Coll., Engineering Expt. Sta., BUZZ. Series No. 2.

(8) Saunders, Brit. J. ExptZ. Bid., 4, 46-72 (1926). (9) Schreiber, J. Am. Chem. SOC., 32, 978 (1910).

pp. 19-28 (June, 1930).

(10) Suter and Moore, Rept. N . Y . State Conservation Comm., 1922,

(11) Thompson, Pub. Puget Sound Bid. Sta. Univ. Wash., 5, 277-

(12) Wisconsin State Board of Health Rept., “Stream Pollution in

292.

92 (1927).

Wisconsin,” pp. 76-83, Jan., 1927.

RECEIVED October 30, 1931. Presented before the Division of Water, Sewage, and Sanitation Chemistry a t the 81st Meeting of the American Chemical Society, Indianapolis, Ind., March 30 to April 3, 1931.

Slotted Watch Glasses for Use in Electroanalysis EARLE R. CALEY, Frick Chemical Laboratory, Princeton University, Princeton, N. J.

OR the prevention of loss by spraying or splashing F during electrolytic determinations, the slotted watch glasses shown in the figure have been found to be a decided improvement over the perforated or split watch glasses usually employed for this purpose. Watch glasses with one or more holes drilled in them protect solutions satisfactorily during electrolysis, but the necessity of disconnecting the electrodes each time a watch glass is to be placed on or removed from a vessel renders their use inconvenient, whereas the divided type of watch glass frequently causes difficulty or loss be- cause of its tendency to be easily jarred out of position.

The preparation of slotted watch glasses of the types shown, from plain watch glasses, presents no especial difficulty providing there is available a sufficiently thin Carborundum wheel. In making form A , which is designed for use with stationary electrodes, an ordinary watch glass is simply slotted by means of the grinding wheel. In the preparation of form B, which has been found more satisfactory for use with a rotating anode, the central hole is drilled first in the usual manner before the slotting operation is performed. In order to minimize the risk of breakage during grinding, it is necessary to select the rather thick variety of plain watch glass in preference to the thin kind.

Several practical precautions must be observed during the grinding operation in order to prepare these slotted watch glasses successfully. In the first place, the speed of the wheel should be kept low, preferably at about 400 r.p.m., and lubrication with Carborundum powder and water should be generous during the entire operation. It is quite essential to introduce the edge of the glass to the wheel slowly and to maintain a slow rate during grinding. Good technic requires

A 6 TYPES OF SLOTTED WATCH GLASSES

that the wheel be worked back and forth in the partly formed slot following each new advance so that a slight enlargement is continually produced. An average-sized watch glass should

224 A N A L Y T I C A L E D I T I O N Vol. 4, No. 2

require from 20 to 30 minutes for slotting. Finally, the glass niust be held in a firm and fixed manner while grinding so that no undue strain is exerted on that portion of the slot already formed. When properly performed, the above process produces a neat clean-cut slot free from any sign of chipping,

These slotted watch glasses have been used frequently by the author and by students in this laboratory and have proved very satisfactory for covering beakers during elec-

trolytic determinations. Undoubtedly similar ones or suit- able variations of them might well find application in other situations where it is desirable to provide a cover glass that may be readily removed and replaced in spite of obstructions that would otherwise interfere

The writer wishes to acknowledge his indebtedness to E. W. Wilson, glassblower at the Frick Chemical Laboratory, for supplying the practical details of the above method. R E C E I V ~ D November 30, 1931.

Multiple- Range Flowmeters SAMUEL YUSTER, University of Minnesota, Minneapolis, Minn.

N THE study of gaseous reactions by flow methods, it is often advantageous to have a multiple-range flow- I meter because of the necessity of a wide range in rates of

flow in the problem. In many cases the range is varied by inserting capillaries of different size by means of rubber tubing, but rubber has the disadvantage of aging and leaking, and corrosive gases attack it.

During the course of some work on halogenation, the flow- meters described in this article were designed and found to work very satisfactorily. Their ranges are changed simply by turning the stopcocks.

In Figure 1 the gas passes in at A and through capillary D or E, according to the range desired, and out again at B. By turning stopcock C through an angle of 180 degrees, the two capillaries are alternately placed in the line. After sealing the flowmeter into the line, the manometer limbs are

n I

degrees, closing off both D and E, and the new range may then be adjusted.

If a three-way stopcock is not available, the capillaries may be sealed on in parallel, using one ordinary two-way stopcock for each.

In Figure 2 the gas passes in at A and up into C, which is joined to the rest of the flowmeter by a ground-glass joint. The gas then goes down the capillary which is in mesh with B and out to the rest of the line. C is held to the rest of the apparatus by means of wire or small springs and the arms M , 0, and P.

n

FIGURE 1

filled through stopcock F. If too much manometer liquid is allowed to flow in, or if it is necessary to change the liquid, it may be removed through stopcock G. H and Z are constric- tions which smooth out any pulsations in flow due to the passage of the gas through a wash liquid. The bulb J pre- vents the manometer liquid from being blown into the line because of a sudden rush of gas. The liquid is merely blown into the bulb and when conditions are normal again, it drains back into the limbs of the manometer.

If more than two ranges are desired, another ensemble of a three-way stopcock and two capillaries may be sealed on a t A and B. Stopcock C is then turned through an angle of 90

FIGURE 2

To change the range of this flowmeter, C is rotated through such an angle as to bring the proper capillary in mesh with B. Although only the two capillaries D and E are shown in the drawing, three or four may be sealed on, giving as many ranges In filling the manometer arms, C is removed and the liquid introduced.

ACENOWLEDGMENT The writer wishes to acknowledge the helpful suggestions

of A. Cameron in the design of these flowmeters.

RBCEIV~D January 4, 1932