CHINOLINE AND ITS HOMOLOGUES. 387 



Nitrate of Chinoline. — In some respects my experiments on this salt tally with 

 those of Dr Hofmann, in others they differ considerably. It was obtained by the 

 last-named chemist by allowing a mixture of leukol and dilute nitric acid to rest 

 under a bell-jar; after some time the salt crystallized in confused concentric 

 needles, which were obtained white and dry by pressure between folds of filter- 

 ing paper. He does not appear to have analysed it. I found that if, after an excess 

 of nitric acid slightly diluted was added to chinoline, the fluid was evaporated on 

 the water-bath, a pasty mass was obtained, which solidified on cooling. From a 

 hot alcoholic solution fine white needles soon deposited, which were infusible at 

 212°, and unalterable in the air. Dr Hofmann, on the contrary, found his salt 

 to fuse on moderate heating, and to rapidly become blood-red by exposure to the 

 air ; these are, evidently, the characters of an impure substance. The nitrate of 

 chinoline was burnt with oxide of copper, a long column of copper turnings being 

 placed in the front of the tube. 



{6-590 grains of nitrate of chinoline, dried at 212°, gave 

 13-516 ... carbonic acid, and 

 2-530 ... water. 



Experiment. Calculation. 



Carbon, . . . 55-94 56-25 C 18 108 



Hydrogen, . . . 4-27 4-17 H 8 8 



Nitrogen, . . . ... 14-58 N 2 28 



Oxygen, . . . ... 25-00 6 48 



100-00 192 



Chinoline gives a very marked reaction with strong fuming nitric acid, and 

 which also shows its great stability. If a few drops of the base are allowed to 

 trickle down the side of a test-tube, and a small excess of the acid is added, the 

 two combine with violence, the portion of alkaloid adhering to the sides is con- 

 verted by the fumes of the acid into long needles, and, when cold, the whole fluid 

 solidifies to a beautifully white crystalline mass of pure nitrate. No nitrochino- 

 line, or any other decomposition product, is formed, if the base be free from im- 

 purities. 



Bichromate of Chinoline. — Gerhardt, in describing this salt,* merely states, 

 that chromic acid in solution gives, with pure chinoline, an orange-yellow crys- 

 talline precipitate, and that the dry acid decomposes the base with inflammation, 

 Dr Hofmann, in his paper on the coal bases, previously referred to, states that, a 

 short time after he had commenced the investigation of leukol, he was inclined 

 to consider it the same as that Gerhardt obtained by the action of hydrate of 

 potash on quinine, cinchonine, and strychnine. He says, however, that he soon 

 convinced himself that they were totally distinct, their behaviour towards a 



* Traite de Chimie Organique, troisieme partie, p. 150. 



