H8 as CO>*BE. 



more of the taste of burnt sugar, but neither bitterness nor 

 harshness. Infused in hot water it gave out neither more 

 taste, nor more aroma. 

 Very highly No. 3. was reduced to powder very easily. To cold 



roasted water it imparted scarcely any aroma: its taste was empy- 



reumatic, and slightly bitter: and the precipitate it afforded 

 with solution of gelatine was hardly perceptible. The in- 

 fusion in hot water was more bitter, more empyreumatic, 

 and had a more distinct aroma. 

 Hoastjiif in- AH these infusions contained mucilage and gallic acid, but 



creased the j n an inverse ratio to the tannin; for the proportions of 

 diminished the g um an d ac»d increased with the degree of torrefaction, 

 tannin. while the tannin diminished. 



Gallic acid a Mr- Bouillon Lagrange, in an excellent paper on galls,* 



modification of na d already considered the gallic acid as a modification of 



tannin ; and these experiments tend to confirm his opinion. 



- Examination of the Roasted Coffee. 

 As the immediate principles of coffee are not equally so- 

 luble or volatile, it was necessary to make a comparative 

 examination of the hot and cold infusions of the three sorts 

 of coffee, as well as of their decoctions. 



Infusion in Cold Water. 



Roasted coffee I poured eight ounces of distilled water on one ounce of 

 macerated in roas t e d and ground coffee, and after they had stood toge- 

 ther two hours, I filtered the liquor. Thc v infusion was of 

 a very clear brown, did not redden blue paper, was black- 

 ened by sulphate of iron, and slightly precipitated solution 

 of gelatine. Alcohol separated from it a little mucilage, 

 and gave the infusion the smell of juniper. Mocha, Bour- 

 bon, and Martinico coffee exhibited the same characters. 



Hot Infusion. 



infused, I infused an ounce of roasted and ground coffee for a 



quarter of an hour in eight ounces of water at 70 a (190° F.) 



This infusion did not redden litmus, or precipitate solution 



of gelatine, but formed ink with sulphate of iron. Alco- 



* See Journal, p. 58 of the present Volume. T. 



hoi 



