MUREXIDE. 1 19 



tains no sulphuric acid. By nitric acid it is decomposed with ef- 

 fervescence. When the solution is evaporated and saturated 

 with ammonia, it assumes a purple colour like the solution of 

 uric acid in nitric acid. 



Uramile is soluble in potash ley and in sulphuric acid. It is 

 precipitated unaltered from the former by acids, and from the 

 latter by water. 



When heated with oxide of copper the carbonic acid and azo- 

 tic gases evolved were to each other as 8 : 3. When dried by 

 artificial heat it assumes a slight shade of red. The mean of four 

 analyses in Liebig's laboratory, by means of oxide of copper, gave 

 the constituents of uramile as follows : 



Carbon, . 32-83 or 8 atoms = 6 or per cent 33-56 

 Hydrogen, 3-75 or 5 atoms = 0-625 ... 3-50 



Azote, . 28-72 or 3 atoms = 5-250 ... 29-38 



Oxygen,. 34-70 or 6 atoms = 6-000 ... 33-56 



100-00 17-875 100-00 



Thus it appears, that, at a boiling temperature, thionuric acid 

 is decomposed into one atom of uramile and two atoms of sul- 

 phuric acid. 



1 atom thionuric acid is, . C 8 H 5 Az 3 O 12 S 2 

 1 atom uramile, . C 8 H 5 Az 3 O 6 





Remain O 6 S 2 



which is equivalent to two atoms of sulphuric acid. 



SECTION VII. OF MUREXIDE. * 



This is the substance which Dr Prout first obtained by adding 

 ammonia to a solution of uric acid in nitric acid, and which he 

 described under the name ofpurpurate of ammonia. The pre- 

 paration of it was so uncertain, and depended upon so many 

 circumstances which had not been determined, that scarcely any 

 chemist was able to succeed in obtaining it till the subject was 

 investigated by Wohler and Liebig. 



Dr Prout found that this substance dissolves in the alkalies 

 while ammonia is evolved, and that the acids precipitate from its 

 solution a white or yellow matter in fine brilliant plates. This 

 1 ast substance he called purpuric acid. 



* Ann. de Chim. et de Phys. Ixviii. 314, 



