310 MR C. G. WILLIAMS ON THE VOLATILE BASES 



experiments made by Hofmann, that they had been ascertained, by crucial ex- 

 periments upon perfectly pure substances, to be the same. In the meantime, 

 chinoline is found to be produced from other bodies, among which may be men- 

 tioned thialdine and trigenic acid. 



But if we examine the published analyses of chinoline, great discrepancies 

 appear, so much so, that Gerhardt places two formulae by the side of the analy- 

 tical results, namely, C 18 H 7 N and C, H 9 N. On looking at the experimental 

 as compared with the theoretical results, it appears that the analyses, if we except 

 Hofmann' g, which were made upon the base from coal naphtha, agree with neither 

 view. Bromeis, in a paper on chinoline, published about ten years since,* gave a 

 formula which is not admissible, and his numbers, recalculated according to the 

 new atomic weight of carbon, do not agree with either of the formulas given by 

 Gerhardt, the carbon being two per cent, too low. The analysis of the bases 

 themselves in the present case, is by no means a satisfactory method of establish- 

 ing their constitution, for when entirely freed from other substances, they are ex- 

 tremely incombustible ; and when it is considered that the two formulae only cause 

 a difference of -2 of a per cent, of carbon, it will be seen that the platinum salts 

 afford a far better means of distinguishing them, the addition of C 2 H 2 causing a 

 rise of two per cent, in the carbon. But even this method could not afford a 

 result, where a mixture of substances was present, unless the salt had been frac- 

 tionally crystallized, which does not appear to have been done by either of the 

 chemists who have worked on chinoline ; Bromeis obtaining far too much carbon 

 for the 18, and as much too little for the 20 C base ; the same remark applying, 

 though less strongly, to the results of Gerhardt, whose numbers approach, with 

 regard to the carbon, nearer to the formula C 1S H. N, than C 20 H y N, although he 

 obtained greatly too much hydrogen for either. 



Before I had seen the discordant analyses in the Traitede Chimie Organique of 

 the last-named chemist, I had suspected, upon theoretical grounds, that chinoline 

 was not a homogeneous substance. In the first place, it appeared unlikely that 

 in an operation with so powerful a reagent as caustic potash, acting at an elevated 

 , temperature upon so complex an organic molecule as the base alluded to, that 

 only one substance, and that of so high an atomic weight as chinoline, would be 

 found. I had ascertained, by a great number of experiments on nitrogenized 

 substances, both animal and vegetable, that in no case could they be distilled, either 

 alone or with alkalies, without formation of the pyrrol of Runge, and on trying 

 the same experiment with cinchonine, a similar result presented itself; and this 

 alone was a strong evidence of the truth of the supposition alluded to. But the 

 chief reason which led me to doubt the homogeneity of chinoline was, that I was 

 unable to obtain it with a constant boiling point. I will not lay stress upon an 



* Liebig's Annalen, Bd. 52, p. 130. 



