113 DESCRIPTION OF 



The first variety occurs in nodules or irrej^ular masses, 

 from the size of mustard seed to four or five inches in dia- 

 meter. Its external surface is of a dirty grey colour, cover- 

 ed here and there with pyrites, which substance often pene- 

 trates the whole mass, and on the decomposition of which 

 the whole cracks and crumbles to pieces. The surface is a 

 crust which has in some pieces a thickness of one-eighth of 

 an inch, and of whatever colour and lustre the included Re- 

 tinasphalt may be. Is always uf a dirty grey and dull. 



Its specific gravity varies much, and does not coincide 

 with that given by Hatchet, who states it to be 1.13. I have 

 repeated the experiment several times, and have constantly 

 found that the fragments which did not contain any py- 

 rites, did not exceed 1.04. Some fragments which floated 

 on the surface of the water, I found to be 0.97 and 0.98, 

 and consequently the specific gravity varies from 0.97 to 

 1.04, and is thus lighter than any of the resinous substances 

 in their unaltered state which are found in the drug shops. 

 These, according to Brisson, vary from 1.0183, as Elemi, to 

 1.1363 as Labdanum. I found also my supposition as to the 

 great specific gravity, stated in the above mentioned memoir 

 on amber, ^c. verified ; namely that it was owing to the in- 

 termixture of pyrites, which by its decompositions has crum- 

 bled several specimens. 



CHEMICAL PROPERTIES. 



I digested some of it, broken up into small fragments, in 

 pure alcohol. This fluid exhibited some action on the sub- 

 stance even when cold. In less than an hour, some of the 

 colours, parficularly the lighter ones, had lost their polish, and 

 seemed to be covered with a dull earthy matter. After it 

 had been exposed for two days to the action of alcohol, the 

 whole of its gloss had disappeared, and though the frag- 

 ments had retained their former shape, they had neverthe- 

 less undergone a change in their consUtuents : the alcohol 



