212 On the presence of Pyiidine in Naphtha. 



that no other bases having diflferent per-centages of platinum in 

 their salts were present), unless by supposing thereal boiling-points 

 to be much lower than those indicated by their discoverer, and, 

 in fact, I have since ascertained that he does not by any means 

 insist upon their accuracy. If the suggestion thrown out, of the 

 presence of two bases of the composition of lutidine, be correct, 

 we can easily imagine that to be the cause of the discrepancy; 

 but I have obtained in the ciystallization of the platinum-salts 

 of sethylamine, crops forming together, and yet having no resem- 

 blance in colour or form, some being thin lemon-coloured plates, 

 and others solid deep red prisms, both, however, giving the same 

 results on analysis. 



It is somewhat singular that the so-called quinoline, submitted 

 to fractional distillation, yields a base having a constitution ap- 

 parently closely allied to the pyridine series ; in fact one of the 

 fractions converted into platinum salt yielded exactly the quantity 

 of carbon, hydrogen, and platinum in the base between lutidine 

 and parvoline ; this result, and some others, has induced me to 

 undertake a rigid examination of quinoline. 



It was, unfortunately, impossible to obtain enough platinum- 

 salt of pyridine from the shale products at my disposal for a 

 combustion ; but when we consider that in the bases from the 

 same source I have demonstrated the existence of all the other 

 members of the series, and that the fifth fraction gives exactly 

 the theoretical quantity of platinum, we have no reason to doubt 

 the presence of pyridine ; the more especially, that although the 

 powerfully-odorous picoline is present, it is unable entirely to 

 conceal the overpowering smell peculiar to the former base. 



The difficulties in the way of separating several basic liquids 

 of analogous constitution by fractional distillation is so great, 

 that it would appear quite hopeless to obtain any one product 

 absolutely pure, even where the quantity of material at command 

 is very considerable ; but by first fractionating the liquid by di- 

 stillation and then converting the fractions into platinum- salts 

 and repeatedly crystallizing until the product gives exactly the 

 theoretical quantity of platinum, we may, by distillation with 

 potash, obtain the base in a state fit for examination of its pro- 

 perties. 



To show the connexion between the two series, I append the 

 following table from my former memoir. 



