54 ANIMAL ACIDS CONTAINING AZOTE. 



converted into sulphuric acid and uramile.* It becomes muddy 

 during the boiling, and concretes into a silky mass of uramile, 

 while the sulphuric acid remains dissolved in the water. 



Though thionuric acid contains sulphuric acid, yet the or- 

 dinary reagents are incapable of detecting that acid in thionurate 

 of ammonia. The salts of barytes throw down a thick, flocky, 

 gelatinous precipitate, which is soluble in muriatic acid. The 

 salts of lead behave in the same manner. 



A solution of thionurate of ammonia mixed cold with muriatic, 

 sulphuric, or nitric acids, undergoes no alteration at the com- 

 mon temperature, but when boiled for a few minutes, it becomes 

 muddy, and concretes into a white magma, consisting of micro- 

 scopic needles, having a satiny lustn\ This precipitate contains 

 no sulphuric acid, but consists of uramile. After this decom- 

 position, the sulphuric acid may be discovered in the liquor by 

 the usual reagents. 



The thionurate of lead being analyzed in Liebig's laboratory, 

 was found to be composed as follows ; 



Carbon, . 10-83 or 8 atoms = 6 .or per cent, 10'7 

 Hydrogen, . 1*04 or 5 atoms = 0-625 ... 1-1 



Azote, . 9-47 or 3 atoms 5-25 ... 9-3 



Oxygen, . 10-83 or 6 atoms 6-00 ... 10-7 



Sulphuric acid, 18-05 or 2 atoms = 10-00 ... 17.9 

 Oxide of lead, 49-78 or 2 atoms = 28-00 ... 50-3 



55-875 100-0 



If we admit, with Wohler and Liebig, that the salt is a dithi- 

 onurate, it is obvious that the constitution of thionuric acid is C s 

 H 5 Az 3 O 6 + 2 (S O 3 ) = 29-875. This conclusion was con- 

 firmed by a careful analysis of thionurate of ammonia. Between 

 the tube filled with chloride of calcium, and that containing the 

 caustic potash, a tube was interposed filled with peroxide of lead. 

 This peroxide absorbed the sulphurous acid given out, and con- 

 verted it into sulphate of lead. The mean of three analyses gave 

 the constituents of the salt as follows : 



* This product of uric acid will be described in a subsequent chapter. 



4 



