45 Vegetable Wax. [Bock Vllf* 



tome folid by a very flight degree of coU ; and others 

 again arc almoft always folid : thefe laft are called nut- 

 ters. Such are thofe of the cacao nut, from which 

 chocolate is made, and alfoofthe cocoa-nut. Vegeta- 

 ble wax is of the lame nature, only more folid. It is 

 the production of China ; and is there made into yel- 

 low, white, or green candles, the colour varying accord- 

 ing to the manner in which the wax is extracted. The 

 catkins of birch and poplar afford a fmall quantity of a 

 fimilar wax. M. Berthollet eafily whitens if with oxy- 

 genated muriatic acid. 



Fat oils expofed to the air attract its oxygen, and 

 become acid or rancid. Water and fpirit of wine, by 

 abftracting this acid, deprive them of their ftrong tafte, 

 but never completely reftore them to their original 

 ftate. M. Bertholict has difcovered that fat oils, thinly 

 fpread on the furface of water, and expofed to the air, 

 become thick, and aflume the appearance of wax. This 

 appears to arife from the abforption of oxygen, as 

 the oxygenated muriatic acid produces this change 

 more fuddenly. 



Thefe oils afford by diftillation a fmall quantity of 

 \vater impregnated with a peculiar acid, a light oil, a 

 denfe oil, and inflammable and fixed airs. The quan- 

 tity of charcoal left behind is not abundant. By re- 

 diftilling the firft products-, more- water, and an oil 

 which becomes lighter each time, are obtained. La- 

 voifier collected the products of olive-oil burned in 

 an apparatus properly conftrudted to afcertain their na- 

 ture and properties. He obtained feventy-nine parts 

 cf carbon, and twenty- one of hydrogen, from one 

 hundred of oil. From thefe component parts, infer- 

 ences may be drawn refpecting the acid, the water, the 

 fixed air, and the inflammable air, afforded by partial 

 decompositions or combuftions of this fluid. When 



oils 



