CHEMISTRY. 353 



10. Study of Floating Equilibrium. 



The study of floating equilibrium, already begun by Dr. J. W. 

 Shipley two or three years ago, was continued with the help of G. W. 

 Harris. He studied especially the behavior of different kinds of glass, 

 their thermal hysteresis, and prepared a table of floating temperatures 

 with various concentrations of hydrochloric acid which will enable 

 anyone to standardize a thermometer in this way. For details the 

 published papers already referred to in the last Year Book should be 

 consulted. The method was found to be extremely sensitive, but with 

 sufficient care it is capable of yielding interesting and significant 

 results. 



11. Effects of Isomorphous Impurities on the Transition Temperatures of 



Crystallized Salts. 



With the help of Dr. W. B. Meldrum, the effects of isomorphous 

 impurities on the transition temperatures of crystallized salts were 

 investigated. It was found that the presence of sodium sulphate 

 in sodium chromate raises the transition temperature of the latter salt 

 in a perfectly definite way and a mathematical expression for the effect 

 of increasing quantities was obtained. The details of the phenomena 

 were observed and discussed. The outcome throws light upon the 

 mechanism of solid solution in cases of this sort. 



A number of papers concerning some of these and some of the pre- 

 ceding researches were prepared during the winter. Reference to these 

 is to be found in the bibliography. On the v/hole the outcome of the 

 year's work under this series of grants was perhaps more successful 

 than that of any previous year. 



Sherman, H. C, Columbia University, New York, N. Y. Continuation of 

 the chemical investigation of the amylases. (For previous reports see Year 

 Books Nos. 11, 12.) 



The investigation as previously outlined has been continued during 

 the past year. Progress has been made in the study of the purification 

 of malt amylase, its chemical nature, its amyloclastic and saccharogenic 

 activities under the influence of different electrolytes, and its behavior 

 toward solvents and under the ultra-microscope. Preliminary exper- 

 iments upon a fungus amylase have also been started and a beginning 

 has been made in the study of methods for the detection and measure- 

 ment of proteolj^tic action, to be used in determining whether the amy- 

 lases of plant origin are possessed of proteolytic power comparable with 

 that which we found in pancreatic amylase in 1912. 



The preparations of malt amylase made during the past year show 

 a much higher average activity and a much closer approach to uni- 

 formity of power than in any previous work. Nevertheless the maxi- 

 mum activities obtained in 1912-13 and in 1913-14 were in close agree- 



