A NEW ORGANIC BASE FROM COAL-TAR. 127 



From these analyses are deduced the following atomic weights : — 

 I. II. 



1211-1 1213-7 



Tliese agree sufficiently well with the theoretical atomic weight, which is 

 1164-5. They correspond also precisely with the results of the analysis of the 

 aniline salts. The identity of these results is shewn by the following table of 

 the analyses by Feitsche, Zinin, and Hoffman, of aniline from its diflFerent 

 sources, and of picoline, as well as of the plantinurii salts of these substances : — 



Aniline.* Benzidam.* Cyanol. Picoline. Theory. 



C = 77-73 77-32 76-67 77-17 77-29 



H = 7-60 7-50 7-72 7-69 7-43 



If = 14-98 14-84 15-62 15-14 15-28 



100-31 99-66 100-00 100-00 100-00 



The following are the results for the platinum salts : — 



Benzidam. Kyanol. Picoline. Theory. 



Mean platinum, per cent. 32-501 32-886 32-533 32-94 



Atomic weight . 1216-1 11705 12124 1164-5 



The results of all these analyses agree perfectly with one another ; but the 

 properties possessed by picoline differ from tliose of aniline, which, whether ob- 

 tained from coal-tar, indigo, or nitrobenzid, presents a perfect identity in its 

 chemical characters. 



Properties of Picoline. 

 Picoline is a perfectly colourless, transparent, limpid iiuid, extremely mobile, 

 and destitute of viscidity. It possesses a powerful, penetrating, and somewhat aro- 

 matic smell, which, when very dUute, is replaced by a peculiar rancid odour, ad- 

 hering pertinaciously to the hands and clothes. Its taste is acrid and burning when 

 concentrated ; but when very dilute, as, for instance, when its vapour is sucked 

 into the mouth, it is powerfully bitter, as are also the solutions of its salts. It is 

 not changed by exposure to a cold of 0°. Picoline is extremely volatile, and eva- 

 porates rapidly in the air. It boils at the temperature of 272°, and the thermo- 

 meter remains perfectly stationary during the whole period of the ebullition ; it 

 is, therefore, much more volatUe than aniline, which, according to Hoffman, 

 boils at 359°. It may be preserved for a long time in a bottle containing only a 

 small quantity of it, and which is frequently opened, without becoming manifestly 

 coloured ; whereas aniline becomes rapidly brown, and, indeed, cannot easily be 

 obtained colourless, except by distillation in a current of hydrogen. The specific 



* Not having' the original papers of Fbitsche and Zinin at hand, I extract these two results from 

 Berzelius' Arsberattelse, 1844, p. 454, where they are calculated according to C= 75-12, the rest are 

 with C = 75, but the diflference is so small as not to affect the comparison. 



VOL. XVI. PART II. 2 K 



