Dr. Hofmanu on a New Class of Organic Bases. 69 



hydrogen on dinitronaphtallne, and gives a fuller account of the pro- 

 ducts obtained in this process. The basic substance arising from 

 dinitronaphtaline crystallizes in colourless needles of great brilliancy, 

 which contain 



C,„H,N,orC,„H,„N,. 

 It is a well-defined basic body, which Zinin describes under the 

 name of seminaphlalidam. From this later communication it would 

 appear that the copper-red coloration originally observed was due 

 to the presence of a foreign colouring matter, which can be separated 

 by crystallizing the base alternately from alcohol and water. 



Subsequently the copper-red body appears to have been observed 

 by Laurent*, who states that the action of sulphuretted hydrogen 

 upon dinitronaphtaline gives rise to the formation of a carmine-red 

 alkali. He did not, however, analyse this substance, and the dis- 

 covery of nitranilinef having established the existence of basic nitro- 

 substitutes, the compound in question was hitherto believed to be 

 nitro-naphtylamine. 



The red crystals have of late been nihiutely investigated in my 

 laboratory by Mr. Charles Wood, whose experiments have led to an 

 unexpected result, which I beg to lay before the Society. 



A current of sulphuretted hydrogen transmitted through a boiling 

 solution of dinitronaphtaline in weak alcoholic ammonia slowly reduces 

 the nitro-compound. The process is continued for two or three hours, 

 during which time the greater part of the spirit distils off ; the residue 

 is acidified with dilute sulphuric acid, and the liquid heated to ebul- 

 lition. The filtered liquid deposits on cooling a j^llowish brown 

 sulphate, which may be purified by several crystallizations from boiling 

 water. The addition of ammonia to the solid sulphate immediately 

 changes the colour to a fine dark carmine-red ; the base thus libe- 

 rated is washed with cold water, and finally purified by crystaUization 

 from water or very dilute alcohol. 



Thus prepared, the substance, for which Mr. Wood proposes the 

 name ninaphtijla7mne, is a light flocculent mass, composed of little 

 acicular crystals, which are partially decomposed by exposure to a 

 temperature of 100° C. It is difficultly soluble in boiling water, but 

 extremely soluble in alcohol and ether. 



In the analysis of the base dried in vacuo over sulphuric acid, 

 Mr. Wood has obtained results which lead to the formula 



C,JI,N,0,. 

 This expression was confirmed by the examination of several of 

 the salts of the new base. 



Sulphate of ninaphtylamine is obtiiined either by recrystallizing 

 the crude salt formed in the preparation of the body, or by dis- 

 solving the ])ure base in dilute sul[)huric acid. It forms white 

 scales, which are apt to be decomposed by recrystallization from pure 

 water. The salt dried in vacuo over sulphuric acid contains 

 2(C,,II,N,0,), II,S,0„. 



* Comjit. Rend. xxxi. 538. 



t Mubpratt and llofmann, Memoirs of the Chemical Society, vol. iii. 111. 



