CHEMISTRY. 355 



4. The Effect of Pressure on the Solubility of Sodium Sulphate. 



Continuing the work conducted during the previous year by Dr. 

 Sill, we sought by this investigation to study with great precision the 

 thermodynamic relationships involved in a typical case. The experi- 

 mentation was conducted by Otto Maass (1851 exhibition scholar 

 from Montreal). The results were interesting, including not only 

 the direct determination of the quantity in question, but also the 

 change of volume on solution, the heat of solution, and other data 

 concerned in the thermodynamic relationship. 



5. Surface Tension of Carbon Compounds. 



In the Year Book of last year the work done by Mr. L. B. Coombs 

 with the support of the Institution was briefly reviewed; this work 

 has since been published. The present research was a continuation 

 of this, in the hands of Eimiiett K. Carver. Part of the preliminary 

 work was repeated and verified, new results on other substances were 

 obtained, and especial attention was given to the vexed questions 

 concerning the shapes of the meniscus and the other minor correc- 

 tions. This research will be continued during the coming winter. 



6. The Silver Coulometer. 



Norris F. Hall continued the study of the irregularities of this 

 instrument, investigating the causes of inclusion of mother liquor, 

 the influence of various impurities, and especially the effect of varying 

 the state of the cathode. The discover}^ of the Bureau of Standards 

 that platinum black upon the surface of the cathode diminishes the 

 amount of the deposited silver was confirmed; it was shown that this 

 source of error could not have greatly affected the earlier Harvard 

 data found by Dr. Anderegg, but that it was probably large enough 

 to render doubtful some of the more subtle conclusions drawn from 

 those results. These matters are to receive further attention in the 

 near future, and a fuller report may well be deferred. 



7. The P^lectromotive Forces Between Different Concentrations of 

 Liquid Sodium Ajialgams. 



Conducted by Dr. J. B. Conant, this research was a continuation 

 of similar work of this kind described in previous Year Books and in 

 Publications 56 and 118. Sodium was chosen because of its univalent 

 nature and its great heat of amalgamation. The high chemical 

 activity of these amalgams necessitated many modifications of 

 apparatus too complex to be described here, and interfered with the 

 certainty of the results; but there seems to be no doubt that sodium 

 amalgams show the same phenomena as thalUum amalgams in greatly 

 exaggerated degree, as had been expected. 



