PARABANIC ACID. 41 



liquid ammonia and in nitric acid. 100 parts of the salt prepar- 

 ed without ammonia yielded 70-6 parts of oxide of silver. Hence 

 it was composed of, 



Parabanic acid, 2 9 '4 or 12-06 



Oxide of silver, 70-6 or 29 = 2 atoms. 



100-0 



100 parts of the same salt, which had been thrown down by 

 ammonia, contained 70*11 of oxide of silver, and, therefore, was 

 composed of, 



Parabanic acid, . 29-89 or 12-34 



Oxide of silver, . 71-11 or 29= 2 atoms. 



100-00 



The mean atomic weight of parabanic acid deduced from these 

 two analyses, (supposing the salt to contain two atoms of oxide of 

 silver,) is 12-2. 



The crystals of parabanic acid were analyzed three times suc- 

 cessively in Liebig's laboratory. The mean result of these an- 

 alyses give the composition as follows : 



Carbon, . 31-66 



Hydrogen, . 1-95 

 Azote, . 24-62 

 Oxygen, . 41-77 



100-00 



We have just seen that the atoms of azote are to those of car- 

 bon as 1 : 3. But if we were to calculate the number of atoms 

 on the supposition that 24*62 represented only 1 atom of azote, 

 we would obtain 7*125 for the atomic weight. While from the 

 analysis of parabanate of silver we know that the atomic weight 

 is above 12. It is clear from this that the acid must contain 2 

 atoms of azote. Hence its constitution must be, 



Six atoms carbon = 4*5, or per cent, 31-58 



Two atoms hydrogen = 0-25 . 1-75 



Two atoms azote = 3-5 . 24-56 



- Six atoms oxygen =6-0 . 42-11 



14-25 100- 



This would make the atomic weight of parabanic acid 14-25. 

 But the atomic weight deduced from the parabanate of silver is 

 12-2. The difference amounts to 2-05, or very nearly two atoms 



