116 Dr. A. W. Hofman on the Organic Bases 



investigations is, however, by no means complete, indeed we 

 possess but a comparatively small number of elementary ana- 

 lyses of the many compound bodies which originate from de- 

 structive distillation. Without a knowledge of the constitu- 

 ents of those fluids, the numerous analogies which they pre- 

 sent to groups of other bodies must be inexplicable, and much 

 of the scientific interest attaching to them is lost. 



There is, therefore, in this subject an extensive field open 

 for investigation. 



About ten years since Runge* published a comprehensive 

 series of interesting researches upon coal-gas naphtha. He dis- 

 covered in it no less than six different bodies, which he desig- 

 nated by the following names, derived from their most pro- 

 minent features, &c. : cyanol, leucol, pyrrol ; carbolic, rosolic 

 and brunolic acids ; the three former act as bases, and the three 

 latter are of an acid or at least an electro-negative nature. 



Of these substances, carbolic acid, cyanol and leucol are ex- 

 ceedingly interesting; the two first-mentioned particularly 

 were studied by Runge more extensively than the others, but 

 their elementary composition was not ascertained until lately, 

 when Laurentf analysed carbolic acid, which he denominated 

 hydrate of oxide ofphenyle, and from the study of the products 

 of its decomposition made it the basis of an interesting class 

 of compounds. 



It appeared to me to involve sufficient interest to make the 

 other two basic bodies, cyanol and leucol, the subject of further 

 researches, and especially to ascertain their elementary com- 

 position. 



Preparation of the Bases. 



The coal-gas naphtha which I employed was obtained from 

 the asphaltum works of Dr. Ernest Sell, at Offenbach on the 

 Maine. The crude naphtha from the Belgium gas-works un- 

 dergoes distillation in large iron retorts. In this process there 

 passes over a large quantity of different oils, and in the alem- 

 bic remains a black, viscous fluid, which upon cooling solidifies 

 to an elastic mass of a brilliant colour. The oils which first 

 distil over are lighter than water, those following are heavier] 

 both mix with each other, and those which pass over last be- 

 come solid in a short time, from the deposition of naphthaline 

 in enormous quantities. In the course of the operation ammo- 

 nia is also disengaged, which is almost entirely dissolved. 

 The products are again submitted to distillation with the ad- 

 dition of a small quantity of sulphuric acid, in order to free 



• Poggend. Annul. Bel. xxxi. pp. 65 and 513, and Bd. xxxii. pp. 308 and 

 328. 



f Annul, dc Chim. et de Phj/s. ser. iii. torn. Hi., p. 195. 



