THE ASH OP PLANTS. Ill 



acids. In the pure state it is a colorless, oil}' liquid, having the odor 

 of tobacco iu an extreme degree. It is inflammable and volatile, and so 

 deadly that a single drop will kill a large dog. French tobacco contains 

 7 or 8 p. c.; Virginia, 6 or 7 p. c.; and Maryland and Havauna, about 2 p. 

 c. of nicotin. Nicotin contains 17.3 p. c. of nitrogen, but no oxygen. 



Ciiffein, C 8 H 10 N 4 O 2 , exists in coffee and tea combined with tannic 

 acid. In the pure state it forms white, silky, fibrous crystals, and has a 

 bitter taste. In coffee it is found to the extent of one-half per cent ; in 

 tea it occurs in much larger quantity, sometimes as high as 6 per cent. 



Xlico1>romin, C 7 H 8 N 4 O 2 , resembles caffein in its characters, 

 and is closely related to it in chemical composition. It is found in the 

 cacao-beau, from which chocolate is manufactured. 



The alkaloids are remarkable from containing nitrogen, and from hav- 

 ing strongly basic characters. They derive their designation, alkaloids, 

 from their likefless to the alkalies. 



CHAPTER II. 



THE ASH OF PLANTS. 



v -L 

 THE INGREDIENTS OF THE ASH. 



As has been stated, the volatile or destructible part of 

 plants, i. e. the part which is converted into gases or vapors 

 under the ordinary conditions of burning, consists chiefly 

 of Carbon, Hydrogen, Oxygen, and Nitrogen, together 

 with minute quantities of Sulphur and Phosphorus. 

 These elements, and such of their compounds as are of 

 general occurrence in agricultural plants, viz., the Organic 

 Proximate Principles, have been already described in detail. 



The non-volatile part or ash of plants also contains, or 

 may contain, Carbon, Oxygen, Sulphur, and Phosphorus. 

 It is, however, in general, chiefly made up of eight other 

 elements, whose common compounds are fixed at the ordi- 

 nary heat of burning. 



