COFFEE. 113 



volatile aromatic principle, with a portion of lime, potash, 

 charcoal, iron, &c. Roasting developes the soluble prin* 

 ciples. Mocha coffee is, of all kinds, the most aromatic 

 and resinous. M. Cadet advises that coffee be neither 

 roasted nor infused till the day it be drunk, and that the 

 roasting be moderate. 



M. Bigio, of Venice, has succeeded in extracting from 

 coffee a green gum lac, said to be useful and beautiful in 

 painting. 



Dr. Moseley, in his learned and ingenious Treatise, 

 states, that " the chemical analysis of coffee evinces that 

 it possesses a great portion of mildly bitter, and lightly 

 astringent gummous and resinous extract, a considerable 

 quantity of oil, a fixed salt, and a volatile salt. These 

 are its medicinal constituent principles. The intention of 

 torrefaction is not only to make it deliver those prin- 

 ciples, and make them soluble in water, but to give it a 

 property it does not possess in the natural state of the 

 berry. By the action of fire, its leguminous taste and 

 the aqueous part of its mucilage are destroyed ; its saline 

 properties are created and disengaged, and its oil is 

 rendered empyreumatical. From thence arise the pun- 

 gent smell, and exhilarating flavour, not found in its 

 natural state. 



" The roasting of the berry to a proper degree, requires 

 great nicety. If it be underdone, its virtues will not be 

 imparted, and in use it will load and oppress the stomach : 

 if it be overdone, it will yield a flat, burnt, and bitter 

 taste ; its virtues will be destroyed, and in use it will heat 

 the body, and act as an astringent. The closer it is con- 

 fined, at the time of the roasting, and till used, the better 

 will its volatile pungency, flavour, and virtues, be pre- 

 served. 



" The influence which coffee, judiciously prepared, 

 imparts to the stomach, from its invigorating qualities, 



i 



