Atomic Laws of Thermochemistry . 53 



From COS,/(S : C : 0) =78, but/(C0 2 ) = 135'3, 



/./(C0 2 )-/(S:C:0)=57'3; 

 so that 



/(CO,) -/(CS S ) = 2 {/•(C0 2 ) -/(S : C : 0)} nearly. (59) 



We have introduced the corresponding data for here 

 because of the mutual action which we found two C : O 

 bindings to exercise, and the method of treatment of the data 

 for CS 2 and SCO has shown that the C : and the C : S 

 bindings exercise the mean influence of two C:S and two 

 C:0 bindings ; for, denoting the mutual influence of two C : S 

 bindings on one another by a, of two C : by /3, and aC:S 

 and a C : by 7, then we have the relations 



2{/(C:0)-/(C:S)4-/3-«} = 117'8, 



/(C : 0) -/(C : S) + 2/3-2 7 = 57«3, 

 and the approximate inference 



2{/(C : 0) -/(C : S) + 2/3-2 y } = 2{/(C : 0) -/(C: 8) +£-«}, 



whence 



27=a + /3=« + 15. 



Thus from the data for CS 2 and SCO we get 



2/(C:S) + 2«=17-5, (60) 



/(C : S) +/(C : O) + 2 7 = 78'0, but/\C : 0) =53, 



.-. /(0:S)+«=10; (61) 



or, in the mean from (60) and (61), 



/(0:S)+« = 9. (62) 



From methyl cyanate we get 



/(C/S-c)+/(C;N)=2-i ; 



but/(C:N) = nearly, .'. /(C'S'C) =2'1 nearly— a value in 

 good agreement with that in (58). 

 3 From methyl isocyanate or methyl sulphocarbimide we get 



/(C/N)+/(C:N)+/(C:S) = 9-0; . . (63) 



whence, as /(ON) and probably /(C : N) are small, /(C : S) 



= 9-0 nearly, which along with (62) makes a small, say zero. 



The two compounds for which we have not reproduced 



Thomsen's data are thiophene and allyl sulphocarbimide, 



