OXALURIC ACID. 43 



The mean of two analyses in Liebig's laboratory gave the con- 

 stituents of oxaluric acid as follows : 



Carbon, 27-06 or 6 atoms = 4*5 or per cent. 27-27 

 Hydrogen, 3-07 or 4 atoms = 0-5 . 3-03 



Azote, 21-05 or 2 atoms = 3 -5 . 21-21 



Oxygen, 48-82 or 8 atoms = 8-0 . 48-49 



100- 16-5 100- 



Its atomic weight is 16*5. It is easy to see how, by boiling, it 

 is decomposed into urea and oxalic acid. 



Oxaluric acid is C 6 H 4 Az 2 O 8 



2 atoms oxalic acid are C 4 O 6 



1 atom urea . C 2 H 4 Az 2 O 2 



Making together . C 6 H 4 Az 4 O 8 

 which is obviously an atom of oxaluric acid. 



When crystallized oxaluric acid unites to oxide of silver, it 

 parts with an atom of water, which is replaced by an atom of 

 oxide of silver. This is obvious from the composition of oxalu- 

 rate of silver. The mean of three analyses give 

 Oxaluric acid, . 51-28 or 15-26 



Oxide of silver, . 48-72 or 14-5 = one atom. 



100- 



The atomic weight of the acid united to the oxide of silver is 

 15-26, while that of the crystals is 16-5 ; the difference, 1-24, is 

 very nearly an atom of water. Hence the acid, when in com- 

 bination with oxide of silver, is C 6 H 3 Az 2 O 7 = 15-375. This 

 constitution was confirmed by an analysis of oxalurate of silver 

 by means of oxide of copper. 



Oxalurate of ammonia crystallizes in silky needles. It is 

 very soluble in hot, but little soluble in cold water. When 

 heated to 212 it loses no weight. The mean of two analyses by 

 means of oxide of copper gave, 



Carbon, 24-07 or 6 atoms = 4-5 or per cent. 24-16 

 Hydrogen, 4-85 or 7 atoms = 0-875 . 4-70 



Azote, 28-08 or 3 atoms = 5 -25 . 28-19 



Oxygen, 43-00 or 8 atoms = 8-00 . 42-95 



18-625 100-00 



