ON A NATURAL SYSTEM 



$ xxxii. Nature of Fofflh dlfcwcrabk by tbe Aid 

 of Cbemijlry. 



IN order to difcover the proximate principles 

 of folliis, it is necellary to have recourie to che- 

 mical experiments. But \vill not the fimpier 

 kinds be fuflicient, in which the foffiis, whether 

 alone, or with the addition oi' proper fluxes, are 

 niched in the fire and treated in various ways? 

 This indeed ii the path purfued with indefatiga- 

 ble zeal by the celebrated Pott, and which no 

 one iince him has extended uirh more fucctfs 

 than the renowned Monfieur D'Arcet. Iio\v 

 far it is connected witli our delign we fliull pie- 

 fen tly have occalion to obitrve. 



J xxxni. Tbfir Cba rafter in tbe Fire. 



A Tiioftouci! knowledge of the effects produ- 

 ced by lire upon ibflllsisof the ^reaitfl importance 

 in the cultivation ot * many arts. For if we re* 

 collect that bricks, tiles, crucibles, gluts, a- 

 mtiufu, earthen and china velleb, cliquation </f 

 metais, and other works, can neither be carried 

 on nor completed without the uillilancc ot lire, 

 we lhall fee that tliis knowledge is equally 

 necciiary and extcnfivc% 



^ XXXI V, 



