contained in Coal-gas 'Naphtha. 117 



them entirely from ammonia. As soon as the lighter oils 

 (which are employed for dissolving caoutchouc) have passed 

 over, the receiver is changed in order to collect the heavier oils, 

 which still continue to deposit a large proportion of naphtha- 

 line. The bases of Runge, as I ascertained readily from pre- 

 liminary experiments, are most abundant in the heavier oils. 

 At first I followed Runge in his investigations, but his method 

 is exceedingly tedious, there is indeed no limit to rectifications. 

 I am inclined to believe the supposed necessity for their end- 

 less repetition has deterred others from repeating and extend- 

 ing his experiments; hence these bodies have not for a long 

 time engaged the attention of chemists, as they would other- 

 wise have done from their properties and chemical deportment. 



The method I arrived at after some experiments on a small 

 scale was very simple. I transmitted a stream of hydrochlo- 

 ric acid gas through the oil until its absorption had ceased, 

 which at first was very active. I then agitated the solution 

 with water, which dissolved the combinations of the acid with 

 the basic oils, and also a small quantity of chloride of ammo- 

 nium. When the red aqueous liquid had separated from the 

 undissolved oil, it was drawn off with a siphon and evaporated 

 over a fire until pungent vapours escaped, which indicated 

 that the bodies in solution began to be decomposed. I filtered 

 the solution carefully in order to get rid of all the uncombined 

 oils, which were only mechanically mixed with the fluid, and 

 had separated in globules during the concentration, and de- 

 composed the clear solution with caustic potash. Globules 

 immediately appeared in the liquid, which after some time 

 floated upon the surface, of a dark brown colour, emitting an 

 insupportable smell. 



This brown oil is a mixture of cyanol and leucol, containing 

 small quantities of ammonia, resinous matters (formed by the 

 action of the air upon the bases), and traces of a volatile sub- 

 stance with a rancid odour (perhaps Runge's pyrrol?), which 

 I have not hitherto perfectly isolated. 



I have employed this method with a few variations for the 

 production of larger quantities. My friend, Ernest Sell, had 

 the kindness to offer me the use of his laboratory : without his 

 kind support it would have been almost impossible for me to 

 have proceeded with my researches. 



Impregnating large quantities of oil with hydrochloric acid 

 gas would have been very tiresome. [ therefore agitated from 

 1000 to 1200 pounds of coal-gas naphtha in large carboys 

 with crude concentrated hydrochloric acid. After the lapse 

 of twelve hours the fluids had separated by virtue of their dif- 

 ferent specific gravities, and the undissolved oil floated on the 



