the Constitution of Carbon Compounds. 99 



mation of methylamine from atomic carbon being 46760 units, 

 that of ammonia 11310 units, and that of methylene 2r or 

 30000 units. 



46760 = (0, H 2 ) + i(N 2 , 3H 2 ) + (CH 2 , NH 3 ) ; 

 .-. (CH 2 ,NH 3 ) = 5450 units. 



An almost identical value (5530 units) was previously de- 

 duced from the heat of formation of cyanogen for C : N. 

 Hence Thomsen concludes that the interpretation thus put upon 

 the reaction involved in the formation of methylamine is 

 justified. 



If methylamine be represented by the formula H 2 C : NH 3 , 

 the formulae of di- and trimethylamine will be 



^ : }nH 2j HaCANH. 



M3 °-J H 3 0.J 



The heat of formation of the group associated with the hydro- 

 carbon radical in each of these amines may be calculated 

 from the following equations : — 



C : NH 3 =2C . N + 3N . H-- pj . N = 16510 units. 



Q : JNH 2 =3C.N + 2N.H-iN.N= 13170 „ 



c':i 



C.VNH=4C.N+ N.H-iN.N= 9830 „ 

 O.l 



The value of C.N has previously been determined ; that of 

 N . H is given by the equation 



6N.H = (N 2 , 3H 3 )+N.N + 3H.H; 



but we have no means of determining H . H. Hence 



N.H = 5940 + IH.H and J(2N . H 2 ) = 5940. 



Adding the values for the hydrocarbon radicals, the heats of 

 formation of the three methylamines will be as follows : — 



Found. 

 Methylamine = 2*- + 16510= 46510 46760 



Dimethylamine = 5r + 13170= 88170 87740 



Trimethylamine = &r+ 9830 = 129830 128690 



If aniline were constituted like methylamine, it would be 

 represented by the formula C 6 H 4 : NH 3 ; but in a body of 

 this formula the nitrogen atom would be united to two carbon 

 atoms, as each carbon atom in benzene carries but a single 

 hydrogen atom, so that if it be assumed that in the amines 

 the nitrogen is always combined with only a single carbon 



