MUUEXIDE. 123 



They found that murexide may be prepared with great faci- 

 lity by putting uramile in boiling water, and adding by little and 

 little, small quantities of oxide of silver or oxide of mercury. 

 The oxides are reduced, the liquid assumes a deep purple colour, 

 and when filtered yields pure crystals of murexide. No gas is 

 given out during the process. 



The slightest excess of oxide causes the red colour to disappear. 

 The liquid becomes colourless, and contains an ammoniacal salt, 

 which behaves with the salts of silver and barytes like alloxanate 

 of ammonia. 



When the crystals of murexide are heated, they lose between 

 three and four per cent, of water. 



The analysis of murexide occasions some difficulty, in conse- 

 quence of the readiness with which protoxide of azote is formed. 

 It was avoided by causing the gases to pass through very fine 

 copper filings raised to the requisite temperature. The propor- 

 tion of azotic gas to that of carbonic acid gas, the mean of four 

 experiments, was 2 '084 of the former, to 4*994 of the latter, or 

 as 2 I 4 '7 9, or very nearly as 5 : 12. 



The mean of five analyses in Liebig's laboratory, by means of 

 oxide of copper, gave 



Carbon, 33-61 or 12 atoms = 9-00 or per cent 33.97 



Hydrogen, 3-00 or 6 atoms 0-75 ... 2-83 



Azote, . 32-70 or 5 atoms = 8-75 ... 33-01 

 Oxygen, 30-69 or 8 atoms = 8.00 ... 30-19 



100-00 26-5 100-00 



The formula C 12 H 6 Az 5 O 8 agrees very well with the analysis, 

 and its accuracy has been corroborated by Wohler and Liebig 

 by the following considerations : 



Murexide is obviously not an ammoniacal salt; but an amide 

 though a kind of amide hitherto without analogy. The problem of 

 the exact formula would have been easily resolved, if, by its 

 decomposition, it had only given two products like the amides. 

 But it gives origin to five different bodies, susceptible themselves 

 of being altered by the agents employed to destroy the murexide. 

 This leads to the supposition that secondary products are pre- 

 sent. 



A boiling solution of murexide, treated by sulphuric or mu- 

 riatic acid, deposites in a short time pearly plates, which are white, 



