206 PROFESSOR T. ANDERSON ON THE PRODUCTS OF THE 



below the boiling point of the oil. A little unchanged pyridine distils at first, 

 accompanied by a small quantity of a light oil, insoluble in water, having a pun- 

 gent smell similar to, and yet appreciably different from, that of pyridine ; and 

 which, as we shall afterwards see, appears to be a mixture of several bases. As 

 the temperature rises, a thick, heavy, and yellowish oil, having a peculiar smell, 

 in no degree pungent, but dull, heavy, and somewhat resembling that of soot, 

 passes over. As the distillation proceeds, crystals make their appearance in the 

 neck of the retort. At a certain stage of the process the product becomes nearly 

 solid, and on cooling, crystals are deposited from the fluid distillate. Towards the 

 close of the distillation some ammonia and very volatile bases are evolved, obvi- 

 ously produced by the decomposition of the oil passing over ; and a dark resinous 

 mass remains in the retort, which can be forced over by raising the temperature, 

 in doing which a large part of it is decomposed, and a residue of charcoal is left 

 in the retort. 



The products of the action being obviously complicated, the whole was 

 cautiously redistilled, and the portion which solidified in the neck of the retort 

 collected apart, while the fluid portions having been introduced into a freezing 

 mixture of snow and salt, soon gave an abundant crop of crystals. These 

 were purified by pressure between folds of filtering paper, and crystallisation 

 from water or alcohol, in both of which they are soluble, until they have lost the 

 smell of the oil by which they are accompanied. 



After having proceeded some way in the investigation, I found that the same 

 substances could be obtained with greater certainty by a modification of the pro- 

 cess just described. It is by no means necessary to heat the sodium and pyridine 

 together, for the action takes place in the cold ; but in this case it is slower, and 

 the phenomena are somewhat different. The brown appearance on the surface 

 of the sodium and the purple streaks appear in the fluid at the beginning of the 

 action, but the pyridine does not become brown, it retains its colour, and the 

 sodium is covered with a black crust, which, after two or three days, exceeds it in 

 bulk, is quite brittle, and sometimes shows a tendency to separate into layers. The 

 pyridine acquires a yellowish tint, and then contains in solution an oil insoluble 

 in water. When the action is judged to have gone sufficiently far, the sodium 

 with its crust is removed from the fluid and washed with a small quantity of 

 pure pyridine, so as to get rid of any of the oily base which may remain attached 

 to it. The crust is then detached as thoroughly as possible from the sodium and 

 thrown into water, any sodium still adhering to it burns, and a dark gray, almost 

 black, powder falls to the bottom of the glass. This is washed first by decanta- 

 tion, and afterwards on a cloth filter until it is free from soda, and on being 

 opened out and exposed for some time to the air, it is entirely converted into a 

 snow-white mass of interlaced acicular crystals identical with those obtained by 

 the first process. 



