NEW LAW IN THERMOCHEMISTRY I9 



Thomsen's data go, conform to the one type of formula, in which 

 instead of c^, the factor ^c^ appears, thus. 



4^ 



12(7 -{- 6d — c —S^i — 8^^ 



= constant. 



The data for nine available compounds are these ; c, being the 

 number of oxygen molecules or pairs of atoms contained in the 

 quadrupled compound. Acetic anhydride approximately fol- 

 lows the same rule. 



Mean, 

 Omitting ethylene glycol, 



Mean, 13777 



In the esters the internal oxygen has still another value, which 

 is represented in the general formula by ^c^. The formula now 

 becomes 



4^ 



— — '- — = constant, 



12a + 00 — c — 4^^ — o« 

 and the data are as given in the subjoined table : 



