ANALYSIS AND ADULTERATIONS OF COFFEE. 81 



insoluble dregs of the coffee. Among some of the Eastern 

 nations the custom prevails of drinking the grounds along with 

 the infusion of the coffee ; in these cases the full benefit is ob- 

 tained from all the positively nutritive matter which the roasted 

 coffee contains. 



It has been found that 1,000 grains of the wood, leaves, and 

 twigs of the coffee-tree yielded 33 grains of ashes, or 3.300 per 

 cent. The ashes consist of potass, lime, alumina, and iron in 

 the state of carbonates, sulphates, muriates, and phosphates, 

 and a small portion of silica. According to Liebig's classifica- 

 tion of plants, the coffee-tree falls under the description of 

 those noted for their preponderance of lime. Thus the pro- 

 portions in the coffee-tree are 



Lime salts 77 



Potass salts 20 



Silica 3 



100 



Coffee contains a considerable quantity of fixed oil and an 

 astringent acid allied to the taniiic. The following is the aver- 

 age composition of raw coffee : 



Woody matter 34 



Water 12 



Fatty matter 13 



Gum, sugar, and Caffeic acid 18 



Caffeine 2 



Azotized matter analogous to legumin 13 



Saline matter, essential oils, etc 8 



100 



It may be interesting to mention among the curiosities of 

 chemistry, that a most magnificent purple dye can be prepared 

 from the alkaloid of coffee. It is analogous to the dye which 

 produced the famous Tyrian purple, unsurpassed for its per- 

 fection and permanence of tint. 

 4* 



