DESTRUCTIVE DISTILLATION OF ANIMAL MATTERS. 573 



that, if a mixture of two such bases were partially saturated by an acid, the salt 

 produced should consist chiefly of the stronger base, and consequently should 

 give a large excess of hydrogen. Salts prepared in this way gave the exact 

 results required for pyridine, as will be seen in a subsequent page. 



Pyridine and its Compounds. 



In the second part of this paper a very cursory account was given of pyridine 

 and its platinum salt, at a time when I had obtained this beautiful base in com- 

 paratively small quantity. Subsequent experiments have afforded me a much 

 larger supply, and rendered it possible to submit it and its compounds to a more 

 minute investigation. It is a transparent and colourless oil, with a powerful 

 pungent smell, soluble in water in all proportions, and obtained absolutely dry 

 only with some difficulty. It boils at 242°, and its specific gravity at 32° F. is 

 0-9858. It precipitates the salts of zinc, iron, manganese, and alumina in the 

 cold, nickel only on the application of heat, and the precipitate dissolves in 

 excess. Copper gives a pale blue precipitate, soluble in excess of base with a 

 deep blue colour, not distinguishable from that produced by ammonia. It has a 

 remarkable tendency to form double salts, most of which are highly crystallizable, 

 and retain the metallic oxide in a state in which it cannot be precipitated by 

 excess of pyridine. An analysis gave — 



r 3-175 grains of carefully dried pyridine gave 

 < 8-830 ... carbonic acid, and 

 { 1-950 ... water. 



Calculation. 



Carbon, .... 



Hydrogen, ... 



Nitrogen, 



100-00 79 



The density of the vapour of pyridine determined by Dumas's method, gave- 



75-84 



"75-94 



c 10 



6<T 



6-82 



6-33 



H 5 



5 





17-73 



N 



14 





i. 



ii. 



Temperature of the air, 



14° cent. 



15° c. 



„ vapour, 



. 164 „ 



143° 



Excess of weight of the balloon, 



. 0-3088 grammes. 



0-4060 gr. 



Capacity of the balloon, 



305 c. c. 



324 c. c. 



Barometer, .... 



765 m. m. 



752 m. m 



Residual air, 



14 c. c. 



>> 



Density of vapour, . 



2-912 



2-920 



The formula Ci H 5 N requires 



10 vol. carbon vapour = 0-8290 x 10 = 8-2900 



10 ... hydrogen ... =0-0692 x 10 = 0-6920 



2 ...nitrogen ... = 09713 x 2=19426 



10 9246 



2-734 



