OXAMIDE. 259 



or by the reaction of ammonia upon oxalic ether, a reaction 

 more accessible to measurement. 



A + 2CAO, 



In fact, the reaction of ammonia upon oxalic ether is 

 immediate. This circumstance was taken advantage of to 

 determine the heat of formation of oxamide. For example, 

 1-9495 grm. of oxalic ether and 10 cms. of a very concentrated 

 solution of ammonia were enclosed in a phial, 



(NH 3 3H 2 about), 



the two bodies being brought together in a little receiver 

 immersed in the water of the calorimeter. The reaction is 

 complete at the end of three or four minutes. The products are 

 then mixed with the water of the calorimeter, so as to bring the 

 whole into a state of dilute aqueous solution. 

 All the calculations being made, 1 



(C 2 H 4 ) 2 C 2 H 2 4 pure + 2NH 3 dilute 

 = C 2 H 4 lsr 2 2 solid + 2C 2 H 6 dilute 



gave off + 26-2 and + 26'6, on an average -f 26'4, or 13'2 x 2. 

 Now the formation of ammonium oxalate, by means of 

 oxalic ether and ammonia, in the presence of a large quantity 

 of water 



(C 2 H 4 ) 2 C 2 H 2 4 pure + 2NH 3 dilute 

 = C 2 H 2 4 2NH 3 dissolved + 2C 2 H 6 dilute, 



would give off + 16'0 X 2. 



By subtracting from the difference (16'0 13'2) x 2, the heat 

 of solution of the ammonium oxalate, or 4 x 2, we find that 

 the formation of oxamide from the solid salt, 



C 2 H 2 4 2ISrH3 cryst. = C 2 H 4 lSr 2 2 + 2H 2 liquid, absorbs - 2'4 

 or - 1-2 x 2. 



In the conditions of direct metamorphosis, by the action of 

 heat on ammomium oxalate, the water takes a gaseous form. 

 Hence 



C 2 H 2 4 2NH 3 cryst. 

 = C 2 H 4 T 2 + 2H 2 2 gas absorbs - 217 or - 10'8 x 2. 



From the above measurements we deduce the heat of forma- 

 tion of oxamide from the elements 



C 2 (diamond) + H 4 + N 2 -f 2 . . . . + 140'0. 



3. Formamide. It was found that the transformation of 

 formic amide into formic acid and ammonia (or rather into 



1 The author also studied the action of dilute ammonia upon oxalic 

 ether, dissolved beforehand in a large quantity of water. This reaction gave 

 off + 8-2 x 2. It did not produce oxamide, all the bodies remaining in 

 solution, even after several days, no doubt in the form of oxamic ether. 



s2 



