CHEMISTRY. 337 



of this solid solution, measuring not only electromotive forces and heat 

 of further amalgamation, but also hardness and density. These 

 results round out in interesting fashion our data for the complete 

 discussion of the problems presented by thallium amalgams. 



(8) Heat of DiLrxiox and Heat Capacity of Sodium A^ialgams. 



In order to complete the necessary data for the theoretical study of 

 sodium amalgams, begun by Dr. J. B. Conant some j^ears ago and 

 mentioned briefly in the Year Book of the Carnegie Institution of 

 Washington No. 15 (for 1916), page 355, Mr. John Russell, 1851 exhibi- 

 tion scholar from INIcGill University, investigated carefully, first, the 

 heat of dilution of sodium amalgams, and next, the heat capacity of 

 these interesting binary mixtures. The data make possible an adequate 

 discussion of the thermod3Tiamic beha^aor of sodium in its solution in 

 mercury, similar to that worked out for thallium with the help of Dr. 

 F. Daniels some time since. It is hoped that this discussion may be 

 ready for publication soon. 



(9) Heat of Reaction of Slow Chemical Reactions. 



Mr. Oscar C. Bridgeman began an investigation on the heat of 

 reaction of slow chemical changes, such as the hydrolysis of esters. 

 For this purpose he brought together an elaborate apparatus for the 

 automatic regulation of the outer bath of a calorimeter by means of a 

 synthermal regulator functioning through the help of a selenium cell. 

 The work is not yet sufficiently advanced to report quantitative results, 

 but bids fair to yield an interesting outcome next year. Incidental to 

 this work Mr. Bridgeman ma.de a careful comparison of several ther- 

 mometers used in previous thermo-chemical work v.ith a standardized 

 platinum thermometer, thus putting ma.ny earlier thermo-chemical 

 data in position for publication. 



(10) Aqtteous Vapor-Pressure of Dilute Sulphuric Acid. 



With the help of Mr. A. Sprague Coohdge, an extended study of the 

 vapor-pressm-e of dilute sulphuric acid was begim. The object was to 

 compare this vapor-pressure thermod^Tiamicallj^ with that of the aque- 

 ous vapor from pure water at various temperatures. The tension of 

 water in sulphuric acid was determined by passing a known volume of 

 air through a peculiar and especially adapted series of saturatiag towers 

 containing mixtures of sulphuric acid and water of definite concentra- 

 tion. The sulphuric acid was analyzed by a new method dependent 

 upon viscosity, which will receive especial discussion on pubUcation. 

 Investigations were also made as to the departure from the gas-law 

 of rarefied aqueous vapor, together wdth the extent to which adsorption 

 on the walls of the vessel may vitiate results. 



(11) Adsorption of Vapors by Solids. 



Dr. Emmett K. Cancer (for several years assistant in this labor- 

 atory and now Rockefeller Research Fellow) undertook the study of 



