` in the Island of Trinidad. 257. 
When the dark-brown compact sort was distilled until the 
bulb. of the retort was red. hot, the 4 retained th 
figure ;—the same also took place ifa a. piece was. kept i in a red 
heat for some time in an open crucible. 250 grains of the original 
< substance thus lost 81 grains, — 32,40 per cent., the greatest part of 
which was bitumen; and when the pale-brown earthy sort was sub- 
_ jected to the same process, the loss on 250 grains was 91, — 36,40 - 
« per cent.;—so that the first left a residuum of 169 grains, and the 
second 159 grains. This residuum, or stone, was spongy, and 
easily broken ;—in an open fire it assumed an. ochraceous ap- 
-+ pearance, but was. internally | ian in consequence of the coal 
resulting. from the decomposed bitumen. "The stone. in. me 
cases was similar, excepting that the first sort was. imas 
E TW «100: parts: of it: afforded. —— «it omms Ant 15 
: Silica eas E qii UE do eis Soh gleia 
Po Un qoe Live Mic UR ivt 
$ ` Oxide OF lom NTN moe" LAG 
m  Carbonaceous matter, a estimation, 
- did not, however, repeat the analysis, and ther 
Bet cus o pror of the oo eer a oxide ofi iron as 
ith bi: jen i is totally 
Pur such-like. sub- x 
HE stances, nich tae peen festa rare’ noticed. z^ V M 
2 The true external characters of this stone must, howevei 
remain in some. degree. uncertain, until specimens can be pro- 
; cured which PUEDE: are unmixed with bitumen, or at least : are 
cUVOL. VIII. s du sil "y m cvba sud a= = only 
