che;mistry — NOYEs. 219 



Noyes, Arthur A., Massachusetts Institute of Technology, Boston, Massa- 

 chusetts. Grant No. 576. Researches upon the physical properties of 

 aqueous solutions in relation to the ionic theory. (For previous reports 

 see Year Books Nos. 2, 3, 4, 5, 6, and 7.) $3,ooo. 



During the past year the researches described in previous reports have 

 been continued, especially in the direction of perfecting the method and ap- 

 paratus so as to enable the specific volume, compressibility, and vapor-pres- 

 sure of w^ater to be determined between the critical temperature and 306°, 

 the highest point to which the previous measurements had been carried. The 

 same apparatus will also be used with some modifications for measurements 

 of the electrical conductivity of solutions at these high temperatures. This 

 work, which has been carried out with the assistance of Mr. Roy D. Mailey, 

 will be continued during the coming year. 



Because of its important bearing on the general purpose of these re- 

 searches, which is to so develop the ionic theory as to account for the strik- 

 ing anomalies which solutions of strong electrolytes exhibit, a new line of 

 work has been undertaken during the past year with the aid of Dr. William 

 C. Bray. This consists in a careful study of the effect of salts on the solu- 

 bilities of one another, in order to determine what modifications the well- 

 known principles of solubility-effect applicable to dilute solutions require in 

 cases where the salts exist to a considerable extent in the un-ionized state. 

 The effects of potassium chloride and sulphate on the solubility of potassium 

 perchlorate, and of thallium nitrate, thallium chlorate, and sodium sulphate 

 on that of thallium sulphate have been studied in this way. The results show 

 that the concentration of the un-ionized part of the salt with which the solu- 

 tion is saturated is much less in solutions that contain another salt with a 

 common ion than in pure water, and that the product of the concentration 

 of the ions of the salt saturating the solution is somewhat greater in the 

 former case than in the latter, while these two quantities would remain con- 

 stant provided the substances behaved normally. The deviations in the case 

 of salts of the tri-ionic type are especially striking, and a fuller study of them 

 gives promise of throwing much light on the cause of the anomalies. 



During the past year an article has been published (Jour. Am. Chem. Soc, 

 31, 987-1010) upon the "Conductivity and Ionization of Polyionic Salts," 

 describing the work previously completed with the aid of Dr. John Johnston 

 and described in an earlier report. A paper on the solubility of certain diffi- 

 cultly soluble salts at high temperatures is also about to be published. 



