Memoir upon Coffee. 19 



the French chemists *, I thuik it my duty to extract and 

 publish from M. Paysse's memoir what n)ay be useful. I 

 presented it, therefore, at one of the meetings of the Phar- 

 maceutical Society, and I now publish it in the form of 

 an extract, beginning with its chemical examination : I 

 shall adopt the author's own language. 



Several chemists have successively occupied themselves 

 with the examination of coffee ; but as the methods of ana-, 

 lysis formerly employed had not arrived at that degree of 

 perfection to which modern chemistry has raised them by 

 its numerous discoveries, I thought of resuming the subject, 

 in the hope of throwing some more light upon the compo- 

 sition of a substance so generally in use. It would be su- 

 perfluous to relate the different results obtained from each 

 analysis. I shall therefore confine myself to pointing out 

 those of the most recent authors who have taken up tlae 

 subject, such as Ryhiner and Chenevix, subsequently to 

 Geoffroy, and shall afterwards detail my own observations 

 resulting front actual experiments. 



Being desirous of knowing the particular principle newly 

 discovered in coffee by Mr. Chenevix fj I proceeded to the 

 chemical analysis 'of it as pointed out by him : it will be 

 seen, however, that my results do not always agree with 

 those of M. Chenevix, and that, in place of a principle in 

 which he seems to have discovered nothing at all acid, I 

 found, on the contrary, a new acid strongly characterized 

 and very distinct from all the other acids. 



I reduced into powder 122 grammes 283 milligrammes 

 (four ounces) of coffee, said to be from Martinique : after 

 bavins put 0-318 milligrammes (six grammes) in a glass 

 containing tincture of turnsole, the violet-blue colour ot the 

 latter soon changed into red. 



The same quantity of powder, mixed with a solution of 

 feulphate of oxygenated iron, produced a very fine green co- 

 lour inclining lo violet. 



* See Phil. M»g. vol. xxvi p. 17. 



f Mr. Clitiiivix's paper on tliis subject was originally given in the Philo- 

 sopliical Magazine, vol. xii. p. 350, and ultcrwards ccpicd into the foraign 

 iouruaU. ,„. 



B 2 The 



