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INDUSTRIAL AND ENGINEERING CHEMISTRY
as t o explain large proportions of the discrepancies betareen the two thiochrome values. While making the attempts just described to obtain proof for the validity of either the direct oxidation or the adsorption technique for the thiochrome method, the authors thought that a comparison of values on the same samples by the yeast fermentation method might lend support to one of the thiochrome techniques. They were fortunate to find Dr. Schultz in Dr. Frey’s laboratory willing to make such determinations. His results are tabulated in Table VI with the corresponding Hennessy and Harris values on frozen samples taken from Table I. As may be seen, his are, in several instances, somewhat higher than the Hennessy values but they are decidedly closer to the Hennessy than to the Harris values in those cases where there is a large difference between the latter two. LITERATURE CITED
(1) Am. Assoc. Cereal Chem., Cereal Laboratory Methods, 1941. (2) Andrews, J. S., and Nordgren, R., Cereal Chem., 18,686 (1941). (3) Arnold, A.,and Elvehjem, C. A,, Food Research, 3,367 (1938). (4) Baker, A. Z., and Wright, M.D., Biochem. J., 29, 1802 (1935). (5) Ibid., 32,2156 (1938). (6) Booher, L. E., and Hartzler, E. R., U.S. Dept. Agr. Tech. BUZZ. 707 (1939). (7) Booth, R. G.,J . SOC.Chem. Id.,59, 181 (1940). (8) Christensen, F. W., Latzke, E., and Hopper, T. H., J . Agr. Research, 53,415 (1936). (9) Conner, R. T.,and Straub, G. J., Cereal Chem., 18, 671 (1941). (10) Conner, R. T., and Straub, G. J., IND.ENQ.CHEM.,ANAL.ED., 13,380 (1941). (11) Ibid., 13,385 (1941). (12) Cowgill, G. R.,“Vitamin B Requirements of Man”, Oxford University Press, 1934. (13) Daniel, E. P., and Munsell, H. E., U. S. Dept. Agr. Misc. Pub. 275 (1937). (14) Harris, L.J., and Wang. V. L., Biochem. J.. 35, 1050 (1941).
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(15) Hennessy, D. J., and Cerecedo, L. R., J . Am. C h m . Soc., 61,179 (1939). (16) Johannson, H., and Rich, C. E., Cereal Chem., 18,473 (1941). (17) Kemmerer, A. R., and Steenbock, H., J . Biol. Chm., 103, 353 (1933). (18) Lane, R. L.,Johnson, E., and Williams, R. R., J. NutTition, 23, 613 (1942). (19) McFarlane, W. O.,and Chapman, R. A., Can. J . Research, 19, 136 (1941). (20) McIntire and Elvehjem, University of Wisconsin, personal
communication. (21) McIntire, J. M., Schweigert,B. S., Henderson, L. M., and Elvehjem, C. A,, J . Nutrition, 25, 143 (1943). (22) MacKinney, G.,reference made in ( 6 5 ) . (23) McLaren and Cover, Texas State Experimental Station, per-
sonal communication. (24) Merck and Co., Rahway, N. J., Mimeograph, revised June 6, 1941. (25) National Cooperative Experiment Station Project, Committee onvitamin Assay Methods,Report, Mimeograph (June4,1942). (26) Pyke, M. A.,Biochem. J., 31, 1958 (1937). (27) Ibid., 34,330 (1940). (28) Ibid., 34, 1341 (1941). (29) Pyke, M.A,, J. Soc. Chem. Id.,58,338 (1939). (30) Research Corporation Committee,subcommitteeon fluorometric method, D. J. Hennessy, Chairman, Report; Coleman Electric Co., Technicul BUZZ.T-108,1941. (31) Roscoe, M. H., Biochem. J., 25,2050 (1931). (32) Schultz, A. S., Atkin, L., Frey, C. N., and Williams, R. R., J . Am. Chem. Soc., 63,632 (1941). (33) Waisman, H. A,, and Elvehjem, C. A., “The Vitamin Content of Meat”, Minneapolis, Minn., Burgess Publishing Co., 1941. (34) Wang, Y. L., and Harris, L. J., Chemistry &Industry, 1942,‘27. (35) Westenbrink, A. G. K., and Goudsmit, J., Entymologia, 5,!307 (1938). (36) Widenbauer, F.,Klin. Wochschr., 18,1613 (1939). (37) Williams, R. R., and Spies, T. D., “Vitamin B1 (Thiamin) and Its Use in Medicine”, p. 161,New York, Macmillan Co., 1939. THISstudy was supported by a grant made through the Kational Research Council by the Sational Live Stock and Meat Board.
Constant-Level Feeder for Continuous Evaporation in the Determination of Total Solids M. C. S C H W A R T Z
AND
F. L. G A Y L E ,
Louisiana State University, Baton Rouge, La. i
T
HE apparatus shown in the figure was developed for use in the determination of total dissolved solids in water, and built to
the authors’ specifications by the Scientific Glass Apparatus Company. An apparatus was desired which could be assembled and started quickly; the apparatus herein described has proved successful in a number of actual tests. The evaporator maintains a constant level of liquid in the evaporating dish, D, for continuous evaporation. The volumetric flask, A , is filled to the mark with the solution to be eva orated, B is put inglace, and the unit is then turned over as iiustrated. The liqui rises in B to height E and then ceases t o flow. C and D, the evaporating dish, are added. The solution is siphoned over through C and stops flowing when the level in D reaches a height equal to E. The siphon can be started by blowing in the vent of B. As evaporation proceeds, more liquid flows over, maintaining the original level in the dish. Any slight amount of liquid finally left in C or B can be emptied manually. The evaporation can be carried out on a water bath, steam bath, or electrical hot plate. Under certain conditions, glass in C, in contact with the liquid in the evaporating dish, will be undesirable when extremely pure liquids are evaporated. In such instances resistant glass, Vycor, fused quartz, or metal tubing (suitable for the liquid) can replace conventional Pyrex tubing. ACKNOWLEDGMENT
The authors wish to thank L. J. Lassalle of Louisiana State University for permission to publish the material in this paper. CONTRIBUTION from the Water Teohnology Laboratory, Engineering Expenment Station, Louisiana State University, Baton Rouge, Le.
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