442 



SCIENCE. 



[N. S. Vol. XIX. No. 481. 



Member of General Committee — A. Springer. 

 Press Secretary — G. B. Frankforter. 

 Local Press Secretary — J. H. Knox. 



The papers read were as follows : 



The Ternary System, Benzene, Acetic Acid 

 and Water: A. F. Lincoln, University 

 of Illinois, Urbana, 111. 

 It was pointed out by Bancroft about 

 ten years ago that the equilibria between 

 two non-miseible liquids and a consulate 

 liquid follow the mass law, and that there 

 are only two sets of equilibria. The ap- 

 plication of the law of mass action to the 

 equilibria of these physical reactions has 

 subsequently been demonstrated to hold 

 very closely in the system, benzene, alcohol 

 and water. Waddell concluded from his 

 experiments that the system benzene, acetic 

 acid and water does not conform to the 

 mass law, and that the equilibria can not 

 be represented by expotential formulas. 

 The work on this system has been repeated 

 by the aiithor, who finds that one of the 

 chief sources of error in a work of this 

 kind is the ascertaining of the point of 

 saturation, that is, of equilibrium. Values 

 are given for temperatures 25° and 35°. 

 The data show that the two equilibria can 

 be represented by two expotential formulas 

 and that, as in the case of chemical reac- 

 tions, the exponent is not a function of the 

 temperature. The conclusion is that for 

 the system benzene, acetic acid and water, 

 the equilibria do follow the law of mass 

 action. 



Thermometric Analysis of Solid Phases: 

 "Wilder D. Banceoft, Cornell Univer- 

 sity, Ithaca, N. Y. 



When two different solutions of a three- 

 component system belong in the same field 

 and reach the same boundary curve at the 

 same point, the composition of the solid 

 phase in that field can be deduced from the 

 difference in the concentrations of the two 

 solutions. This method has been applied 



to experiments of Hey cock and Neville on 

 gold and cadmium in tin and other sol- 

 vents, published in 1891. It was shown 

 that the compounds AuCd and AuCdg are 

 formed. Eeversing the process and as- 

 suming the esistence of AuCd, it is pos- 

 sible to calculate the temperature measure- 

 ments of Heycock and Neville. This work 

 was done by Mr. E. S. Shepherd and will 

 be published under his name in the Feb- 

 ruary number of the Journal of Physical 

 Chemistry. 



A Method of Grading Soaps as to their 

 Detergent Power: H. W. Hillter, Uni- 

 versity of Wisconsin, Madison, Wis. 

 When a soap solution is caused to make 

 drops beneath the surface of an oil, the 

 number of drops formed by a given vol- 

 ume of the solution increases with the con- 

 centration of the solution. The increase 

 in the number of drops with increase in 

 concentration is a measure of the increased 

 power of the solution to emulsify oily mat- 

 ter and consequently to cleanse. Advan- 

 tage was taken of this connection between 

 the number of drops and cleansing poAver, 

 to work out a method of determining the 

 cleansing power of commercial soaps. Cer- 

 tain soaps are efficient for use with cold 

 water but not especially good for use with 

 hot water. The reverse is also true. The 

 method grades soaps for these two kinds 

 of use. The cleansing agent is not the 

 alkali of the soap, but the soap in its un- 

 decomposed form. 



The Determination of Gliadin in Wheat 

 Flour by Means of the Polanscope: 

 Harry Snyder, Minnesota Experiment 

 Station, St. Anthony Park, Minn. 

 The various proteids in wheat flour were 

 briefly discussed and the desirability of a 

 rapid and accurate method for the deter- 

 mination of gliadin noted. Methods based 

 upon the use of the polariscope appeared 



