250 Dr. W. Eamsay on Picoline 



pure ammonium platinlchloride, the last of pyridine platini- 

 cliloride. In no case did the amount of platinum found indicate 

 that the base possessed a higher molecular weight than that of 

 pyridine. Simihir results were obtained with the portions 

 which had not been boiled with nitric acid. It is therefore 

 certain that no bases are found, the molecular weight of which 

 is greater than that of pyridine, and probable that pyridine 

 is the only base produced with exception of ammonia. This 

 affords a strong presumption that lutidine is not dimethyl- 

 pyridine ; for, were it produced, it is certainly stable enough 

 to resist decomposition by soda-lime. 



Mr. Dewar mentions in his memoir that he obtained a 

 mixture of dicarbopyridenic acid with another acid of much 

 higher molecular weight, less soluble in water than the 

 above-named acid. Of such an acid I could find no trace ; 

 but the mother liquor of dicarbopyridenic acid, by repeated 

 fractional crystallization from alcohol, deposited very well- 

 formed rhombic crystals, of which I had about a gram at my 

 disposal. This acid gave off a smell of pyridine when rapidly 

 heated, and when gently warmed sublimed, apparently with- 

 out alteration. Its melting- and decomposing-point was 

 216°-5-217° (uncorr.), while that of dicarbopyridenic acid, 

 taken at the same time with the same thermometer, was 

 237°*5. With ferrous salts, dicarbopyridenic acid gives a 

 deep-red coloration, while the new acid gives a yellow colour 

 like that of ferric chloride. The basicity of the new acid, 

 determined by titration with standard potash, was found to 

 be 152 : the potassium salt contained 33'85 per cent, of 

 potash ; the molecular weight of dicarbopyrdenic acid is 167 ; 

 and its potassium salt contains 32*11 per cent, of potassium. 

 The new acid is extremely soluble in cold water and in 

 alcohol, whereas dicarbopyridenic acid is sparingly soluble in 

 cold water. The acid, as well as its lead- salt, which is mode- 

 rately soluble in water, and crystallizes in radiated crystals, 

 was analyzed with the following results : — 



0-4016 grm. of the acid lost, at 110°, 0*0723 grm. This 

 loss consists partly of w^ater and partly of volatilized acid, as 

 I afterwards ascertained. 0*3293 grm. gave 0*5630 grm. 

 CO2, and 0*1154 grm. H2 0, = 46*59 per cent, of carbon and 

 3*83 per cent, of hydrogen. 



The carbon and hydrogen in the lead-salt were also deter- 

 mined ; the lead was unfortunately lost. 



0*4122 grm. of the dry salt gave, on combustion with 

 copper oxide, 0*3170 grm. of CO2, and 0*0565 grm. of H, = 

 20*97 per cent, of carbon and 1*54 per cent of hydrogen. 



