294 RUBIACEA. 
tannin, But Payen’s (as well as Rochleder’s) investigations 
failed to point out the principle to which the changes are due. | 
Very probably they depend upon the decomposition of several 
it is slowly volatilized at the temperature stated; hence the 
roasting of coffee ought to be effected in closed vessels. Be 
heimer (1880) found nearly one-half of the products of roasti 
to consist of palmitic acid, the remainder being acetic a 
carbonic acid, probably acetone, hydroquinone, pyrrol, met 
lamine, 18 to ‘21 per cent. caffeine, and ‘04 or ‘05 cof 
C°H'°O?, to which the aroma of coffee is due; it is an oil 
ing at 195° C. (383° F.), and is probably a methyl ether | 
saligenin. (Stillé and Maisch.) 
The extract from roasted coffee, mean of eight analyses, 
the following composition : 100 parts of coffee yielded to + 
25°50 per cent. of extractive, containing ‘5 per cent. nitrog 
5°18 per cent. oil, 13°14 per cent, non-nitrogenous matter ¢ 
4°06 per cent. ash. (K@nig.) 
Mocha coffee yields as much as 7°84 per cent. of ash—cc 
sisting chiefly of carbonates and phosphates of potassi 
sodium, magnesium, and calcium, the earthy salts amounting 
one-seventh or one-sixth of the weight. 
The percentage of caffeine contained in raw coffee has 
Kind of Coffee. Moisture, Caffeine, - 
p: 100. p-100 
NOPE 6 seas seis sorceccou ctu tae 8-0 ." 1:20 
Guatemala au O6 1°29 
Travancore ste 10°C 1°29 
Liberia (1) 8-0 1°39 
ss (2) rs 8-0 1:39 
Rio een eenee bt diate h ) 9°] 1:20 
