CHEMISTRY — RICHARDS. 223 



taken in order to attain this object at every stage of the process. Concord- 

 ant results have been obtained with hydrochloric acid and sodium hydroxide 

 by means of these two entirely different methods, the result indicating that 

 the usually accepted values for the heat of neutralization are decidedly too 

 low. The investigation is to be continued next winter, and a fuller report 

 may be reserved until a series of figures with different acids and alkalies have 

 been obtained. 



V. The CompressibiHties of Certain Isomeric Hydrocarbons: 



In continuation of the work upon compressibility, the beginning of which 

 is described in Publication No. 7 and continued in Publication No. 76, and 

 in connection with the work above summarized concerning the heats of com- 

 bustion of octanes and xylenes, the compressibilities of these substances at 

 various temperatures was investigated in detail with the help of Prof. C. L. 

 Speyers, formerly of Rutgers College. The effort was made to attain greater 

 accuracy than ever before in this work, and with the help of Dr. P. W. 

 Bridgman, of the Department of Physics of Harvard University, the stand- 

 ard of pressure was verified to a degree of precision far exceeding anything 

 which has hitherto been obtained. It is satisfactory to note, however, that 

 the standard used in the previous work was not sufficiently in error to 

 influence essentially any of the results there recorded. Many slight improve- 

 ments in manipulation were introduced and the method for determining com- 

 pressibility was found to give satisfaction as before. 



Five octanes were investigated with great care. It was found that their 

 compressibilities varied over a much wider limit than their heats of combus- 

 tion, being comparable to the variations in the boiling-point. In general, as 

 had been predicted upon the basis of the theory of compressible atoms, the 

 isomers with higher boiling-points possess lower compressibility; but there 

 are interesting minor variations in these relationships which deserve further 

 investigation. 



Ortho- and meta-xylene and ethyl benzene also were investigated, and it 

 was found here also that the substance with the greatest compressibility, 

 namely meta-xylene, possesses the least density. This investigation also 

 will be continued during the coming winter and a full report will be reserved 

 for a future date. 



In addition to these five researches which have produced results already 

 worthy of publication even if nothing more should be done upon them, sev- 

 eral other researches have been begun or continued, although they have not 

 yet reached as definite a stage. Chief among these is perhaps an investiga- 

 tion of the compressibility of ice. Study of the literature of compressibility 

 has failed to reveal any data upon this subject. Nevertheless, it is one of 

 great interest, not only because of the part played by ice in remodeling the 



