362 CARNEGIE INSTITUTION OF WASHINGTON. 



magnitude of the deviations from the laws of perfect solutions which 

 largely ionized solutes exhibit. At hydrochloric-acid concentrations 

 between 0.1 and 2.0 normal very satisfactory results have been ob- 

 tained, showing that the activities of the ions of the acid pass through 

 a pronounced minimum between these concentrations. More dilute 

 solutions have offered difficulties which require further investigation. 



Incidentally to the investigation of the bismuth-copper equilibrium, 

 Mr. F. W. Hall has determined the solubilit}'^ of bisnmth oxychloride in 

 hydrochloric acid of various concentrations, with the view of deter- 

 mining the bismuth anion-complexes formed in such solutions. 



Finally, reference may be made to the fact that a monograph by 

 F. G. Keyes and R. B. Brownlee, on the thermodynamic constants of 

 ammonia, consisting mainly of "ammonia tables" for the use of 

 engineers, analogous to the well-known ''steam tables," is now ready 

 for pubUcation and will be issued within a few months. The new 

 experimental investigations on which these tables were based, though 

 not directly supported by the grants from the Carnegie Institution of 

 Washington, were carried out in this laboratory in close connection with 

 the similar research made with the aid of those grants by Mr. R. D. 

 Mailey on the thermodynamic properties of water at high temperatures. 



Richards, Theodore W., Harvard University, Cambridge, Massachusetts. 

 Continuation of exact investigation of atomic weights and other physico- 

 chemical properties of the elements and simple compounds. (For previous 

 reports see Year Books Nos. 2-13.) 



During the past winter (1914-1915) the number of assistants con- 

 tributing to the laboratory work in the Wolcott Gibbs Memorial 

 Laboratory was smaller than last year, because it happened that 

 every one of the eleven men assisting during 1913-1914 had been 

 obhged to leave in order to undertake more lucrative employment. 

 Accordingly, with an entirely new corps of assistants, only seven inves- 

 tigations were prosecuted in the laboratory during the winter. These 

 are described below. The comparative freedom from superintendence 

 of laboratorj^ work was welcomed as an opportunity to collate and 

 pubUsh previous investigations; and fourteen papers, all more or less 

 directly concerning work done with the help of these grants, have been 

 pubhshed since the last report. They represent the expenditure of 

 much time and thought. These papers, which afford a much fuller 

 report of the work than is possible in brief abstract, are recorded by 

 title in the bibliography of the Year Book. The laboratory work 

 during the winter of 1914-1915 was as follows: 



1. Atomic Weight op Lead Obtained from Radioactive Minerals. 



The work upon this subject which was described in the last Year 

 Book was avowedly preliminary. Although its outcome has been con- 

 firmed by other less extended researches carried on both in France and 



