133 Royal Society : — 



both in the anhydrous state, for about thirty hours to a temperature 

 of 170^ C, the Hquid will be found to be converted into a black 

 mass, either soft and viscid, or hard and brittle, according to time 

 and temperature. 



This black mass, which adheres firmly to the tubes in which the 

 reaction has been accomplished, is a mixture of several bodies. On 

 exhausting with water, a portion dissolves, while a more or less solid 

 resin remains behind. 



The aqueous solution yields, on addition of potassa, an oily preci- 

 pitate containing a considerable portion of unchanged aniline ; on 

 boiling this precipitate with dilute potassa in a retort, the aniline 

 distils over, whilst a viscid oil remains behind, which gradually 

 solidifies with a crystalline structure. Washing with cold alcohol 

 and two or three crystallizations from boiling alcohol render this body 

 perfectly white and pure, a very soluble substance of a magnificent 

 crimson colour remaining in solution. 



The portion of the black mass which is insoluble in water dissolves 

 almost entirely in dilute hydrochloric acid, from which solution 

 it is reprecipitated by the alkalies in the form of an amorphous 

 piiik or dingy precipitate soluble in alcohol with a rich crimson colour. 

 The greater portion of this body consists of the same colouring 

 principle which accompanies the white crystalline substance. On 

 the other hand, considerable quantities of this crystalline body are 

 occasionally present in the product insoluble in water. 



The crystalline body is insoluble in water, difficultly soluble in 

 boiling alcohol, soluble in ether. From the hot alcoholic solution it 

 crystallizes slowly on cooling in elongated four-sided plates, often 

 grouped round a common centre ; this substance is a well defined 

 base ; it freely dissolves in acids, from which, on the addition of the 

 alkalies, it is thrown down as a dazzling white precipitate. 



The analysis of this new base has led to the expression 



^■3^ Hj, N3, 



a formula corroborated by the analysis of a fine, somewhat difficidtly 

 soluble hydrochlorate, 



C3,H,,N3,IIC1, 



which is obtained by dissolving an excess of the new base in hot 

 diluted hydrochloric acid, when it crystallizes on cooling. 



A further confirmation was furnished by the examination of a 

 bright yellow platinum-salt, 



C3,H,,N3,HCl,PtCl. 

 Both the hydrochlorate and the platinum-salt are extremely soluble 

 in an excess of hydrochloric acid, which has therefore to be carefully 

 avoided in their preparation. 



The phase of the action of bichloride of carbon on aniline, which 

 gives rise to the formation of the new base, is expressed by the 

 equation 



6C,, H, N + a Cli=C„ Hi, N3, HCl + 3(Ci, H, N, IICl). 

 "What is the coustitution of the new body ? It is obviously derived 



