220 REPORTS ON INVESTIGATIONS AND PROJECTS. 



be obtained also concerning the possible retention of traces of water in the 

 lithium perchlorate which serves as one of the standard substances. 



(3) Adiahatic Determination of the Heats of Solution of Metals in Acids: 

 During the winter of 1908-09, with the help of Dr. L. L. Burgess, the heat 



evolved by the action of the more electropositive among the heavy metals 

 upon acids was studied with great care, the object being to secure precise 

 data for thermochemical and thermodynamic computation. These experi- 

 ments have already been described in the report of last year, and in greater 

 detail in a paper published in the Journal of the American Chemical Society. 

 In the course of the work it was shown that much greater accuracy in the 

 determination of the heats of dilution of the acid solutions concerned was 

 needed than had been supposed to be necessary in the past. It was shown 

 that Thomsen's method of applying the heat of dilution to the results was 

 wholly erroneous, and preliminary results for the heat of dilution of the 

 liquids concerned were obtained. Before publishing this latter part of the 

 work it seemed highly desirable, however, to obtain more accurate knowledge 

 concerning these quantities ; and during the winter of 1909-10 a protracted 

 series of very careful experiments was made with a new, more accurate thei- 

 mometer, by Dr. Allen W. Rowe. These not only fix beyond question the 

 heat of dilutions of several strengths of hydrochloric acid, but show the in- 

 teresting fact that zinc chloride, when substituted in small amount for its 

 equivalent quantity of acid, considerably increases the heat of dilution of the 

 acid, whereas cadmium chloride diminishes it. The full details are described 

 in a comprehensive paper which has already been sent to the press. This 

 paper will appear in the Journal of the American Chemical Society and will 

 ultimately be published, it is hoped, among the publications of the Carnegie 

 Institution of Washington in a volume including all the recent thermochem- 

 ical studies carried out at Harvard University. 



(4) The Heat of Neutralization of Strong Acids and Strong Bases: 



This problem, undertaken with the help of Dr. Rowe and discussed in the 

 last report, has been studied further during the year just past. Confirma- 

 tory results obtained in several different ways and with different thermome- 

 ters have made the outcome so certain that the results are now practically 

 ready for publication. 



(5) The Specific Heats of Aqueous Solutions: 



The method already described in the previous report has been improved 

 so that results of very great constancy and reliability can now be obtained 

 with a minimum of exertion. During the past winter the specific heats of 

 solutions of hydrochloric, hydrobromic, hydriodic, nitric, and perchloric 

 acids, as well as sodium and potassium hydroxides, have been obtained with 

 Dr. Rowe's assistance. The hydroxide of lithium is now being investigated. 

 Interesting relations have already been detected from the comparison of the 

 ■data for analogous substances. 



