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late had occasion to return to the study of these bodies, and to make 

 an observation which I beg leave to communicate to the Royal 

 Society. 



The product which is formed by the union of one molecule of 

 melaniline and one molecule of cyanogen, the compound known as 

 dicyanomelaniline, 



C 13 H 13 N 3 + (CN) 2 = C l5 H 13 N g , 



has feebly basic properties ; it dissolves in acids, and may be repre- 

 cipitated from these solutions without change. It cannot, however, 

 remain in contact with acids without being entirely altered. After a 

 few minutes the limpid solution becomes turbid, and deposits an in- 

 distinctly crystalline body containing 



C 15 H U N 3 2 , 

 an ammoniacal salt remaining in solution, 



C 15 H 13 N 5 + 2H 2 + 2HC1 = C 15 H n N 3 2 +2H 4 NCI. 

 I have described this substance as melanoximide ; it may be con- 

 sidered as the primary oxalate of melaniline minus 2 molecules of 

 water, which are capable of being assimilated again under the influence 

 of the alkalies, oxalic acid and melaniline being reproduced. 



Dicyanomelaniline, when submitted in alcoholic solution to the 

 action of acids, undergoes a perfectly different change. The boiling 

 solution deposits on cooling splendid needles of an indifferent body of 

 the composition 



_ C 15 _H W N S 3 , _ 

 an ammoniacal salt, also in this case, remaining in solution, 



C 16 H 13 N 6 + 3H 2 + 3HC1 = C 15 H 10 N 2 O 3 + 3H 4 N Cl. 

 Melanoximide, occupying by its composition a place between di- 

 cyanomelaniline and the new compound crystallized in needles, is 

 likewise readily converted into the latter substance. When boiled 

 for a short time with a mixture of alcohol and hydrochloric acid, 

 melanoximide furnishes a solution, which, on cooling, solidifies to a 

 mass of beautiful needles, 



C 15 H n N 3 2 +H 2 + HCl = C 15 H 10 N 2 3 + H 4 NC1. 

 The new compound is insoluble in water, but dissolves easily in 

 alcohol and ether ; it is decomposed by boiling with potassa, giving 

 rise to the formation of a carbonate and an oxalate with reproduction 

 of phenylamine, 



C 15 H 10 N 2 3 + 4KHO = K 2 C0 3 + K 2 C 2 4 +2C 6 H 7 N. 



