30 Mr. W. Sutherland on the Fundamental 



f.c, and the heat representing the work to be done in break- 

 ing the single, double, and treble bindings of two carbon atoms 

 by v h % v 2, and v 3 . The result just given is expressed by the 

 equation 



/.c=12M+t> 2 , 



which in our notation is 



2(0) +/(0O 2 )-/(C:0)= 121-1. . . (2) 



From the heats of combustion of allylene, CHCCH 3 , and 

 ethylene, CH 2 CH 2 , namely 467*5 and 333*3, Thomsen gets 

 the relation 



/. c = 134*2 —t-j— v 3 + v 2 , 



which in our notation is 



2(0) +f(G0 2 ) -/(C-C) -/(C ; C) +/(C : C) = 134-2. (3) 



4. The Influence of Hydrogen. — Compounds such as C 2 H 4 

 and C 2 H 6 , or C 2 tC 3 Cl and 2 H 5 C1, in which the addition of 

 2H to the unsaturated one produces the saturated, show a 

 difference in their heat of combustion amounting to 37*3, or 

 in symbols, 



(0)+/(OH 2 )-/(0-C)-2/(CH)+/(C:C)=37-3. . (4) 



But where the added hydrogen takes up a different function, 

 as in the passage from an aldehyde to an alcohol, the increase 

 in the heat of combustion is 57*8, whence the equation 



(0) +/(0H 2 ) +/(C : 0) -/(OH) -/(C-0) -/(OH) = 57-8. (5) 



Going back to the case of hydrogen of constant function, 

 Thomsen remarks that the sum of 121*1 for and 37*3 for H 

 gives 158*4, which is the heat of combustion of CH 2 ; that is, 

 if we add our equations (2) and (4) we get 



3(0) +/(C0 2 ) +/(0H 2 ) -/(0-0)-2/(CH)=158-4, 



which is practically identical with (1), as it ought to be. 



5. Heat of Combustion of the isolated Carbon Atom. — This 

 is the particular section whose invalidity has seemed to detract 

 from the value of Thomsen' s discoveries, because so much of 

 the rest of his work depends on it. Fortunately it so happens 

 that though the reasoning of the section is unsound, its 

 conclusion when properly interpreted is probably correct. 

 Thomsen supposes an atom of C to be introduced into C0 2 

 in such a way as to produce the compound OC = CO ; and 

 this compound by reason of its double binding would, accord- 

 ing to section 3, have a heat of combustion greater than that 



