b o o k « bafaltes or fcherle; zeolite; and the talky and micaceous
. vy~ . « bodies. The diamond is not ranged under this head.
“ The tourmalin holds a middle place between the genus
«* and the fcherles. 5, terra friicea, procured in its pureft
“ ftate from rock chryftal. This earth is infoluble in all the
acids, except the fluor acid. The profeflor feems to fuf-
“ peCt, that it is, neverthelefs, not a pure primitive or ele-
“ mentary earth. Under this genus rank all the qUartZ tribe 5
“ chalcedon yprobab ly alfo the opal; jafpers; peffojiiexy
“ or chert; feldt fpat; and the yellowiih green cloudy to-
“ paz, or ebryfoprajius. Whether the cornelian, and the re-
** maining part of the flinty itones, belong to this genus, he
0 is yet not able to determine.
** C l a s s I I I . B i t u m e n s ;
“ Or inflammable bodies ; which the author divides only
“ into two genera, under the names o f fulphur and petro-
“ leum. Among the firft rank common brimftone; plum-
“ bago; black-lead or molybdena, a fulphur United to a pe-
“ euliar acid.
“ Under the genera o f petroleum he clafleS the naphtha
“ and rock oil«, coal, and amber. 1’rofeflbr Bergman adopts
“ the opinion o f M. Aublet, concerning the vegetable origin
“ o f ambergreaie But it is very lately rendered more pro-
“ bable, that it is an animal, production, being the fcybala of
“ the whale. This opinion is ingenioufl'y fupported by rea-
“ fon and analogy, as well as by fome fad¥s, in a paper writ-
“ ten by Dr. Schwediawer, in the laft volume o f the Philofo-
“ phical TranfaCtions t.
“ Many mineralogiils will b'e furpfized to fee the diamond
** in the bituminous clafs; yet profeflor Bergman confelfes that
* See Hiftoire des Plantes de la-Guiane F ran co i& j V o LH .-S u p P r 39‘ Co'umarTab. 392*
■f V o l; I I v p . 226— *241*
« h e
he could not find a more proper ftation for i t ; and be juf- c™ !>-
“ tifies himfelf on the following confiderations: it remains 1— rv_l/
“ untouched by all the acids ; it is evaporable in the open
“ fire, appearing to diffipate in a cloud, or lambent flame;
“ and in the focus of the fpeculum it leaves flight traces o f
“ footy remains. This deflagration, howfoever. flow and
“ gentle, he apprehends, reduces it to a place among inflam-
a mable bodies.
H C l a s s IV. M e t a l s .
“ In the introductory feCtion to this clafs, the profeflor
“ aflerts the great affinity that fubfifts between bituminous
•“ bodies and metals, by obferving, that both zinc and arfe-
“ nick flame when properly heated in the fire.
“ He divides metals into noble and ignoble; and treats
“ o f them in the order of their fpecifick gravities.
“ Of gold he enumerates four fpecies, found in a native
“ bate ; and, though he mentions a pyrites aureus (Cronf.
“ §. 166. a), has neverthelefs fome doubts, as to the reality
“ of the mineralization of gold. PlatinaSf, he fays, is always
ffj debafed with a martial admixture. Of filver he gives
“ feven fpecies as native, and eleven mineralized. He attri-
“ butes to Mr. Woulfe the merit of obferving the vitriolick
“ principle in horn filver; and gives him equal praife for
“ his difcovery,that mercury is mineralized by the muriatick
& and vitriolick acids. Under lead, the profeflor mentions
“ a fpecies found by M. Mounet, which is mineralized by
“ means of the vitriolick acid; and another, detected by Dr.
“ Gahn, which is reduced to ore by the phofphorick acid.-
“ He has exhibited, under the article of copper, a fpecies
“ fent to him by Mr. Werner, which he found to be mine-
* C o u n t Sibltingea has la te ly difcoyercd as 18 to i , is now proved to b e as ,31 to 1 ,
a means o f p u r ify in g p la t in a , by whiqh G o ld is ;only as 19 . 6 4 to 1 . See Verfuqh#
that nj.e.tal, b efo re fuppofed to be to w ater ueb er die P latin a . Manhe im.
O o o .a “ ralized
\