Mr. F. Trouton on Molecular Latent Heat. 



55 



between this statement and Dulong and Petit's law, namely 

 that the specific heat multiplied by the atomic weight is a 

 constant quantity. 



The following alcohols form a fairly well-defined class, 

 with which perhaps water may be placed: — 





I. 



II. 



III. 



IV. 



1295 

 12-86 



Water 



537 

 263-7 



9 

 16 



100 

 55 



Methyl alcohol . . . 



Ethyl alcohol ... 



202 



23 



79-7 



13-17 



Auryl alcohol . . . 



121 



44 



134 



13*08 



Cetyl alcohol , , . 



58-7 



121 



350 



11-40 



In column I. are arranged the latent heats, in column II, 

 the densities, in III. the boiling-points of the bodies ; and in 

 column IV. are the products of the latent heat by the density 

 divided by the absolute temperature of the boiling-point. 



In the case of the following acids the theoretic densities of 

 the first two are too small, owing to the vapour-densities being 

 abnormally great at temperatures approaching the boiling- 

 point. This is corrected for in formic acid in the ratio of 2*68 

 to 1*62, and acetic acid in the ratio of 3*19 to 2*08. Without 

 the correction the numbers in the fourth column would be for 

 formic acid 7*44, for acetic acid 7*86. 





I. 



II. 



III. 



IV. 



12-31 



Formic acid 



120-7 



23 







100 



Acetic aoid 



1019 



30 



116 



1205 



Butyric acid 



114-7 



44 



162 



11-59 



Valeric acid 



103-5 



51 



175 



11-78 



The following are the ratios in the case of a few methyl and 

 ethyl salts: — 





I. 



II. 



III. 



IV. 



1038 

 10-59 



Methj-1 iodide ... 

 Ethyl iodide 



46-1 

 46-9 



71 



78 







42 

 72 



