Atomic Laws of Thermochemistry. 51 



and therefore /(OO) = 26-3, 



which is larger by 9 than the value just found in (54), just 

 another such discrepancy as we found above in (52). To try 

 to understand this, let us reproduce side by side equations 

 (51) (52) (53) and (55) and (43) :— 



In the amines with triad N, 



/(ON)=0 nearly; 

 in the nitroparaffins with pentad N 9 



/(C'N)+2/(N:0) = ll-8; 

 in the nitrites with triad N", 



/(C-0)+/(N-0)+/(N:0)=17-3; 

 in the nitrates with pentad N, 



/(OO) +/(N-0) + 2/(N : 0) = 26-3 ; 

 in N 2 6 with pentad N, 



2/(N-0) + 4/(N:0) = 6. 



If we remember that/(O0) is about 18'5, we see that the 

 one consideration which will harmonize the five equations is 

 that the introduction of a second N : binding- into an N 

 atom connected with C or with connected with 0, is 

 attended by an evolution of about 10 kcal. Whether this, 

 besides harmonizing the five equations, is a true phenomenon 

 would require more experimental facts to decide ; but, mean- 

 while, we can claim that the nitroparaffins and the nitrates 

 agree in showing the mutual operation on one another of 

 atoms which are not directly connected, and that there is no 

 necessity to devise a new structure for the nitroparaffins to 

 explain their thermochemistry, because the nitrates by the 

 same token would also require an amended constitution, which 

 is very improbable. 



11. Sulphur 'Compounds. — Thomsen's data for the heat of 

 formation of the sulphur compounds relate to solid rhombic 

 sulphur : the latent heat of vaporization of a gramme-atom of 

 sulphur, according to Berthelot's table of latent heats, is only 

 2*3 kcal.; so that it is only necessary to increase Thomsen's 

 heats of formation by 2*3 per gramme-atom of sulphur to get 

 at least approximate values for the heat of formation from 

 gaseous sulphur. In the following table are given all but two 

 of Thomsen's data for the heats of formation p and p + ad for 

 the sulphur compounds from solid sulphur, along with values 

 of^> and p + ad for gaseous sulphur : — 



E2 



