Chemistry and Physics 37 



object was to extend the study to elements possessing other valences and to study 

 more accurately the phenomena investigated. The electromotive forces (and their 

 temperature coefficients) of various cells containing amalgams of the eight metals 

 named in the title were measured, with many precautions against experimental 

 errors. Thallium and indium were found to behave in the same manner as cadmium, 

 but in a much more exaggerated degree. Tin and lead were found to behave in the 

 same manner as zinc, but likewise in a more exaggerated degree. It was shown 

 that the greater part of these deviations from the concentration law may be explained 

 by the heat of dilution of the amalgam, according to the equation of Cady. The 

 temperature-coefficient of a cell of this type was shown to correspond closely with 

 the requirement of this equation. The difficulties of the actual measurement of 

 thermochemical data involving amalgams were emphasized, and many errors in the 

 work of previous investigators were discovered. It was shown that the deviations 

 from the simple concentration law in every case decreased as the dilution increased, 

 so that upon reaching a concentration of 0.01 gram-atom per liter all the amalgams 

 investigated behaved practically as ideal solutions. 



No. 125. RICHARDS, THEODORE W., and H. H. WILLARD. Determination of Atomic 

 Weights. Octavo, iv+113 pages, 4 figs. Published 1910. Price $0.75. 

 This book contains the following papers, not sold separately: 

 RICHARDS, T. W., and H. H. WILLARD. Further Investigation Concerning the Atomic 



Weights of Silver, Lithium, and Chlorine. 



RICHARDS, T. W. Harvard Determinations of Atomic Weights between 1870 and 1910. 

 RICHARDS, T. W. Methods Used in Precise Chemical Investigation. 



The first paper describes a new method for determining the atomic weight of 

 silver through the ratio of lithium perchlorate to the chloride on the one hand and 

 the ratio of the chloride to silver on the other. A new method of purifying lithium 

 salts is described, as well as new apparatus for effecting the change of the chloride 

 into the perchlorate. Incidentally the atomic weight of lithium was determined anew 

 and found to be nearly 1 per cent lower than Stas's value. If oxygen is taken as 

 16, the investigation yielded as its result Ag = 107.871 and Li = 6.939. 



The second paper contains a brief description of all the investigations concerning 

 atomic weights which have been conducted in Harvard University, with a detailed 

 chronological bibliography and a table comparing the results with the accepted inter- 

 national values. 



The third paper combines the most important parts of two addresses delivered 

 before the German Chemical Society and the American Chemical Society. It 

 emphasizes some of the more important details necessary in exact chemical ex- 

 perimentation of any kind. 



No. 63. The Electrical Conductivity of Aqueous Solutions. A Report presented 

 by ARTHUR A. NOYES upon a Series of Experimental Investigations 

 executed by A. A. NOYES, W. D. COOLJDGE, A. C. MELCHER, H. C. 

 COOPER, YOGORO KATO, R. B. SOSMAN, G. W. EASTMAN, C. W. KANOLT, 

 and W. BOTTGER. Octavo, vi+352 pages, 20 text figures. Published 

 1907. Price $2.50. 



This publication describes an extended series of researches on the electrical con- 

 ductivity of aqueous solutions through a wide range of temperature (18" to 306*). 

 The special apparatus which had to be constructed for the purpose is fully described. 

 The conductivity results obtained with seventeen different salts, acids, and bases at 

 various concentrations are presented in detail ; and these results are discussed with 

 reference to the migration-velocities of the constituent ions and the degree of 

 ionization and hydrolysis of the substances themselves. From the hydrolysis meas- 

 urements the ionization constant of water is derived for temperatures between and 

 306. The general conclusions to which all these researches have led are presented 

 in a comprehensive summary at the end of the work. 



No. 60. JONES, HARRY C., and F. H. GETMAN, H. P. BASSETT, L. MCMASTER, and 



H. S. UHLER. Hydrates in Aqueous Solution. Octavo, vm-j-264 pages, 



35 plates, 76 text figures. Published 1907. Price $2.50. 



In this monograph are brought together the results of several years' work on the 



various lines of evidence bearing upon the "Hydrate Theory." One of the most 



