PETROLEUM.
Phlogiston occurs alſo in the foſſil kingdom, combined in an oily form; but many ſuppose this derived from the vegetable kingdom.
PETROLEUM pure and ſelected.
Cronstedt Min. §§ 147–150. Naptha. Rock oil.
PETROLEUM joined to argillaceous earth.
Cronstedt Min. §§ 157–160. Lithantrax. Pit Coal.
PETROLEUM united to acid of amber.
Cronstedt Min. §§ 133–146. Succinum. Amber.
Many contend that amber has a vegetable origin; but as the point is not very well determined; and as it is found amongſt foſſils, I ſtill retain it here.
Ambergriſe, according to the aſſertion of Mr. Aublett, is nothing more than the juice of a tree inſpiſſated by evaporation into a concrete form. This tree grows in Guyana, and is called Cuma, but has not been inveſtigated by any botaniſt. Pieces of this tree are ſaid to be carried down into the rivers by heavy rains, and the ſpecimens examined by Mr. Rouelle had the odour and principal qualities of amber[[50]]. Rumphius, long ſince, mentioned a tree called Nanarium, whoſe juice reſembled amber[[51]].