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CARNEGIE INSTITUTION OF WASHINGTON. 



constantly increased in resistance, and without subsequent recalibration 

 of the coil it can not be said that its pressure coefficient has remained 

 substantially the same. 



Some work has been done on the osmotic pressure of electrolytes. 

 Owing to the effect which this class of substances has on the colloidal 

 nature of the semi-permeable membrane, the direct measurement of the 

 osmotic pressure of electrolj^tes has not been possible. Efforts have 

 been made to obtain protection of the membrane against this deterio- 

 rating influence. The most recent experiments along this line have 

 been very encouraging. The substance which has been found to exert 

 the greatest protective influence has little protective action on the class 

 of suspensoids, and certain substances which have a great protective 

 action on the suspensoids have apparently no influence in protecting 

 the membrane against electrolytes. A more complete study of this 

 question of protection of the membrane is very desirable. 



Osmotic pressure of glucose. 



Noyes, Arthur A., Massachusetts Institute of Technology, Cambridge, Mas- 

 sachusetts; and Throop College of Technology, Pasadena, California. 

 Researches upon (1) the 'properties of solutions in relation to the ionic 

 theory, and {2) the deierminaiion of the atomic structure of crystalline sub- 

 stances by X rays. (For previous reports see Year Books Nos. 2-15.) 



During the past year the researches described in previous reports on 

 the electromotive forces of voltaic cells and on the vapor-pressure of 

 salt-hydrates have been continued, with the assistance of Mr. R. G. 

 Dickinson. Especial attention has been given to the cell Hg -f- HgO, 

 NaOH in water, Cd(0H)2 + Cd, with the view of determining the 

 free energies of cadmium oxide and hydroxide. 



Much progress has been made, with the help of Dr. John B. Dickson, 

 on a systematic recomputation of the free energies of the oxides, 

 sulphides, and halides of silver, mercury, lead, and copper, based in 

 part on data existing in the Uterature and in part on new measurements 

 of electrode-potentials and of chemical equilibria made in this labora- 



