SCIEKTIFIC WEWS. 153 



fUport of the Proceedings of the Mathematical and Physi- 

 cal Class of the French Institute^ continued from p, 79. 

 Mr. Yaiiqiielin has analysed tobacco, with a view to de-^^^jy^jgof 

 tect the principles, that cliaracterise this plant, and have tobacco, 

 occasioned it to be chosen for the uses for which it is eni^ 

 ployed : and to ascertain the changes produced in it by the 

 preparations it undergoes for sale. It appears to contain an 

 animal matter of the albuminous kind, malate of lime with 

 excess of acid, acetic acid, nitrate and muriate of potash, a 

 red matter the nature of which is unknown, muriate of 

 ammonia, and finally an acrid and volatile principle appa- Peculiar prin* 

 rently different from any other known in the vegetable ciple in it 

 kingdom. It is this principle, that imparts to tobacco its 

 well known qualities; and it may be extracted from the 

 plant by distillation, and employed separately. Prepared 

 tobacco yielded, in addition to the matter above enumerated, 

 carbonate of ammonia, and muriate of lime. 



Mr, Vauquelin imagined, that the juice of belladonna, Analysisof 

 from its effects on the animal economy being analogous to belladonn** 

 those of tobacco, might contain the acrid principle he had 

 discovered in the latter : but pn analysing it he found only 

 an animal matter, salts with base of potash, and a bitter 

 substance, from which the juice of belladonna receives its ; 

 narcotic properties. 



Mr. Chevreul presented to the class a very extensive series production of 

 of experiments on vegetable matters. Te object o f some araere 

 of these ■ "^s the bitter principle produced by the action of . , 



nitric acid an organic matter containing nitrogen. He con- 

 ceives it ii be a compound of nitric acid and an oily or 

 resinous *eoetable matter: and he ascribes its detonating 

 property to the decomposition of the nitric acid, the foi mo- 

 tion of aramoniacal gas, prussic acid, olefiant gas, &c, . - 

 But with the amere is produced a resinous matter, and a 

 volatile acid, on which Mr. C. has made many experiments; 

 jind Which he considers as differing from the amere only by 

 a smalt addition of nitric acid. 



Another obj«ct of Mr. Chevreul was the substances a^fj of aftj^.^j 

 formed by the action of nitric acid on carbonaceous or tannin. 

 lesjnous matters, which have the property of precipitating 



gelatine 



I 



