1805.] 
loft their cylindrical forfn, and are per- 
feétly flattened, as if they had. been fub- 
jected to an immenfe degree of preflure. It 
is commonly of a chocolate-brown ; its 
quality and texture are various in different 
ftrata; from fome of thefe, it is obtained 
in the form of flat pieces, three or four feet 
in length, refembling boards, and is called 
board coal. Others have ana oblique, 
wavy, and undulating texture, and have 
a {trong refemblance to the roots of trees, 
from which, they have, probably, been 
formed. From 200 grains of the Jatter 
were obtained: 
Water oe kre) let ne ° 60 
Oily Bitumens . 2 . . 2m 
Charcoal ot te) 7st 84 |) QO 
Mixed gaffes * e e e e 2 9 
200 
The charcoal refembled that which is 
made of recent vegetables, and by incine- 
ration, about four grains of yellowith 
afhes werelett, which confifted of alumina, 
iron, and filica ; but neither in the Bovey 
coal, nor in the leaves of the Iceland 
{chiftus was there the f{malleft trace of al- 
Kali. 
After a minute and accurate defcription 
and analyhs of the bitumen from Bovey 
coal, itis inferred by Mr. Hatchet that it 
is a peculiar and hitherto unknown fub- 
fiance, which is partly in the ftate of ve- 
getable refin, and partly in that of the 
bitumen called afphaltum, the refin being 
in the largelt proportion, as 100 grains of 
it afforded : 
Refin e é ‘ ° e e 55 
Adphaltumy ol) 683 4t 
Earthy reiduum . . . 3 
= 
99 
Thus we have an inftance of a fubftance 
being found under circumftances which 
conftitute a foffil, although the characters 
of it appertain partly to the vegetable, and 
partly to the mineral kingdom. 
From other expetiments detailed by this 
ingenious gentleman we learn that the 
action of alkohol on the bitumens is very 
flight, and that the fmall porticn of ex- 
tract, which may be thus obtained from 
them is petroleum ; and he alfo infers that 
bituminous fubftances owe their origin to 
the organized kingdoms of nature, elpeci- 
ally to that of vegetables. 
Time alone does not reduce animal or 
vegetable bodies to the (tate of fodfils. 
There are examples of whole forelts which 
have been fubmerged prior to any tradition, 
MonTuty Mac. No. 127, 
Proceedings of Learned Societies. O58 
and’ which neverthelefs, completely retain 
their ligneous charaéters. Other cau(es 
and agents mult therefore have been re- 
quired to form the varieties of coal, and 
other bituminous fubftances. In fome ine 
ftances, as in the formation of Bovey-coal, 
thefe caufes feem to have aéted partially 
and imperfectly, while, in the formation 
of the greater part of the pit-coals, their 
Operation has been extenfive and come 
plete. 
In the pit-coals, the mineral characters 
predominate, and the principal veitige of 
their real origin feems to be bitumen, for 
the prefence of carbon in the ftate of oxide, 
cannot alone be confidered as decifive. 
Bitumen, therefore, with the exuvie and 
impreffions fo commonly found in the ac- 
companying ftrata, muft be regarded as: 
proofs in favour of the origin of pit-coab 
trom organized bodies ; and contidering 
the general faéts, which have been lon 
obferved, together with chofe lately ad- 
duced refpeéting the Bovey-coal, and the 
fubftance found with it, we feem to have- 
evidence, that bitumen has been produced 
by the modification of fome of the proxi. 
mate principles of vegetables, and efpe~ 
cially refin; and Mr. Hatchet gives to the - 
Bovey-coal the name of Retina/phaltum, 
(from enfiwn,refin ; and ac@arloc, bitumen} 
a word by which a full definition of its 
nature is conveyed. 
In the month of June laft, a paper was 
laid before this Society by SMiTHSON TEN- 
NANT, Ef{q. containing an account « OF 
two Metals, found in the blach Powder re# 
maining after the Salution of Platina.” Prior 
to his defcription of the analyfis of this 
black powder, he fays it was obtained 
from very pure platina, that had been prea 
vioufly treed from the {and and other im- 
purities generally mixed with it, fo that: 
it mult have been obtained from the grains 
of platina, It had the appearance of 
plumbago, but its fpecific gravity was 
greater being about 10.7. This powder 
readily unites with lead; but with ten 
times its own weight, the compound whes 
melted, has not much fluidity. . 
In the analy fis of the black powder, Mra 
Tennant made ule of an alkaline folution, 
and an acid folution: the furmercontained 
the oxide of a volatile metal and a {mall 
propertion of the other metal. If this fo» 
lution be kept fome weeks, the latter metal 
{cparates {pontaneoufly from it, in the form 
it, in the form of thin flakes of a dark 
colour, 
The acid folution alfo contains both 
metals, but principally that which Mre~ 
Tennant calls by the name of the Iridium, 
from 
