nally necessary to the forming of the > bitumen in conjunction with 

 the carbon *." 



The origin of AMBER, the next bituminous substance which de- 

 mands our attention, is an enigma, the solution of which appears 

 to be fraught with considerable difficulties. The analysis of this 

 substance, as has been already seen, manifests plainly that it pos- 

 sesses, in every respect, the chemical properties of bitumen. Am- 

 ber, exposed to the fire, liquefies if the heat be strong, softening 

 and bubbling, without running into drops ; which circumstance 

 distinguishes it from the resins. When inflamed, it diffuses a thick 

 smoke, with a pungent odour. Its flame is yellow, but variegated 

 with blue and green. It leaves, after combustion, a black shining 

 coal, which yields by incineration a very small quantity of earth, 

 mixed with a very slight proportion of iron. From these proper- 

 ties we should therefore be led, without the least hesitation, to seek 

 for its formation in the subterranean laboratory of nature ; but for 

 its bearing accidental, but unequivocal marks, of having existed, 

 during some of the stages of the process, by which it has been 

 formed, either actually on, or very near to, the surface of the earth. 



Naturalists have by no means agreed in their opinions respecting 

 the origin of this substance. Theophrastus speaks of amber as a 

 stone, dug out of the earth in Liguria, and which possesses a power 

 of attraction. Sir John Hill, in his notes on this passage, gives it as 

 his opinion that it is, as he says, the best of the modern writers seem 

 certain of its being, a mere native fossil -j-. Dioscorides thought it 

 to be an exudation from the black poplar. Pliny, who particularly 

 noticed this substance, supposed it to have run from the trunks of 

 trees, resembling pines, in the same manner as rosin is known to flow 

 from the pines, and gum from the cherry-trees ; and hence he ima- 



* PhilosophicalJournal, vol. ii. p. 203. 



t Theophrastus on v Stones, translated by John Hill, M. D. p. 133. 



