48 MM. Dumas and Pelletier on Organic Salifiable Bases. [J A n . 



this, and probably the other substances, are much fewer, and 

 the calculated result is rather nearer that obtained by experiment. 



Carbon. .. 20 atoms 6 x 20 = 120 or in 100 parts 75-00 



Azote 1 = 14 8-75 



Hydrogen. 10 =10 6-25 



Oxygen.. 2 8 x 2 = 16 10-00 



"33" 160 100-00 



In concluding, the authors observe, that the results of the 

 analyses of the substances in question are equivalent to 



Carbonic acid. Azote. 



Quinina 100 6-1 



Cinchonia 100 5-0 



Strychnia 100 4-9 



Narcotin 100 4-5 



Brucia 120 5-0 



Morphia 100 3-2 



Veratria 100 3-2 



Emetin 100 3-1 



Cafein 100 20-0 



With respect to the last mentioned substance, MM. Dumas 

 and Pelletier observe, that no particular memoir has as yet 

 appeared upon it. It was discovered in 1821 by M. Robiquet, 

 in his researches to discover quinina in coffee. The authors of 

 this paper obtained the same principle about the same time, but 

 the priority is due to M. Robiquet. The properties of cafein are 

 stated to be, that it is white, crystalline, volatile, and but slightly 

 soluble. 



The method of analysis adopted was that suggested by Gay- 

 Lussac ; the peroxide of copper employed was prepared by cal- 

 cining the nitrate at a dull red heat; it was then carefully 

 washed, and again heated at the same temperature to expel the 

 moisture ; and before use it was moderately heated in a platina 

 crucible, and weighed while still warm. 



MM. Dumas and Pelletier adopt the specific gravity of 

 gases as determined by Dulong and Berzelius, and their calcu- 

 lations are founded on the weights of atoms given by the same 

 chemists. 



