Inflammables. 
flame, and when diftilled yields bituminous oil, infoluble 
in water, leaving a carbonaceous reflduum. Specific gra¬ 
vity, nearly that of water; fome varieties more, fomelefs. 
8 . Bitumen gagas,’hard bitumen, or jet: compact, 
deep black, opake, of a conchoidal texture, Alining in¬ 
ternally, burning with a greeniih flame. Found in va¬ 
rious parts of Great Britain, France, Spain, Germany, See . 
particularly on the coaft of Loweftoft in Suffolk, with im- 
preflions of cornu ammonis ; fometimes ^n layers, but 
generally in kidney-form mafles of various fizes. Colour 
glofly black, glafly internally; texture ftriated, and con- 
choidal. When cpld has no odour, but when heated 
emits an odour refembling that of afphaltus ; readily in¬ 
flames, and lofes during combuflion 14grains in 20,leav- 
*► ing an earthy reflduum ; in thin pieces will float for a 
Ihort time on the water; fpecific gravity, 1-259. It is 
formed into buttons, beads, and other trinkets. When 
heated, or rubbed hard, will attract light bodies. 
9. Bitumen amphelites, cannel-coai, or bovey-coal: 
black, opake, brittle, does not ftain the fingers, burns 
with a bright light flame like a candle. Found in Lan- 
cafliire, Ireland, and many parts of Europe, of a com¬ 
pact flaty texture, and conchoidal frafture ; it kindles ea- 
flly, and leaves a Aony or footy reflduum of a grey colour; 
it is lufceptible of a fine polifh, and like jet may be made 
into trinkets. Specific gravity, 1-232 to 1-426. 
The following interelling account of the Bovey-coal is 
from Kidd’s Outlines of Mineralogy, lately publifhed.— 
“.The fubfiance fo called, confifts of the branches, trunks, 
and roots, of trees, that have, to a greater or lei's extent 
in different parts, undergone that alteration by which the 
vegetable principles are charred and converted into bi¬ 
tumen. Bovey-coal is analogous to the J'urturbrand of 
Iceland; the piligno of the Italians; and the feverai va¬ 
rieties of bituminous wood, fometimes called lignite, met 
with in different parts of Europe. The general appear¬ 
ance of Bovey-coal, and the alluvial charafter ot the 
Ipot where it is found, fufficiently manifeftits origin ; and 
fliow that the alteration it has undergone depended on a 
procefs analogous to that which takes place in the for¬ 
mation of turf and peat. Some fpecimens have been 
lately fent to the mufeum at Oxford, which have every 
appearance of the recent vegetable ; they appear to have 
belonged to that part of the trunk which is contiguous 
to the root; and are of the character of a fpecies of fir. 
I underfland from a gentleman who is thoroughly ac¬ 
quainted with all that part of Devonfliire, that theftrata 
of Bovey-coal originate from a part of the heath where 
numerous flumps and roots of trees are remaining ; that 
from this point the ftrata generally dip, or incline down¬ 
wards beneath the furface; fo that, in proportion as you 
advance from the roots juft mentioned, the accumulation 
of alluvial matter above the coal becomes thicker. The 
Bovey-coal appears therefore to be the broken trunks 
and branches of the roots and flump juft mentioned. From 
the completely-vegetable appearance of the fpecimens 
above mentioned, the Bovey-coal may be traced by infen- 
flble gradations into a ftate in which every feature of the 
vegetable is loft, and the fubftance in colour and luftre 
and frafture completely refembles pitch. In one part of 
the heath I met with a few fmall pieces that exaftly re- 
lembled common charcoal, but were more eafily divilible, 
and almoft crumbled between the fingers. I did not fub- 
mit thefe to a chemical examination; but I found that, 
when they were employed for the purpofe of completing 
the galvanic circle, no fpark was produced, whereas in 
the cafe of common charcoal a fpark is produced. In 
fome inftances the Bovey-coal is obtained in the form of 
ftraight flat pieces, three or four feet in length, refem¬ 
bling boards: in which ftate it is called loarcl-coal. The 
flattened form' of fubftances originally cylindrical, as the 
trunks and branches of trees, is obferveable in the J’urtur- 
hrand, or bituminous wood, of Iceland, as well as in the 
Bovey-coal; and alfo in other limilar fituations ; and the 
obfervation extends to all organic remains met with in 
Vol. XV. No. 1058. 
* 
Inflammables. 477 
ftrata of clay, or argillaceous- fchift; for thefe are con- 
ftantly of a flattened form, even in the cafe of bone and 
fliells ; fo that the fome fubftances, which in a calcareous 
ft rat uni preferve for inftance their original cylindrical 
figure, in a ftratum of argillaceous fcliiftus are comprefled 
into a plane triangular furface.” 
10. Bitumen lithanthrax, common or pit coal: opaque, 
black, brittle, burning with a blackifli or grey fmoke, and 
leaving black or grey allies and cinders. "For a full hif- 
tory of coal and coal-mines, with a defeription of the-me- 
tliod of working them, and a Plate of machinery, fee 
Coal, vol. iv. p. 703-712. 
11. Bitumen oxygenatum, or Kilkenny.coal : opake, 
black, very brittle, not ftaining the fingers, burning with 
little or no fmoke or flame, or flaming with iridelcent co¬ 
lours, leaving a very fmall quantity of whitilh allies. There 
are two varieties: 
a.. Stone-coal ; of a flaty texture and conchoidal frac¬ 
ture, with a glafly internal luftre. / 3 . Culm. ; of a fibrous 
texture and rather conchoidal frafture, with lels internal 
luftre, and often intermixed with powdered carbon. Both 
forts occur in various parts of Wales, particularly round 
Swanfea, and in Ireland, in ftrata and veins like common 
coal. It burns very flowly, with great heat, without 
flame, or with purple, yellow, and white, iridefeent co¬ 
lours, and is ignited with much difficulty; during com- 
buftion it emits faint fuffocating vapours like charcoal 
and is therefore dangerous to ufe in fmall dole rooms ; 
while burning, it explodes and flies about. Culm is con- 
fiderabiy' contaminated with powdered carbon, which may 
be eafily rubbed off, and then it does not ftain the fingers : 
it contains near 80 per cent, of pure carbon. Stone-coal 
is principally ufed for malting ; and culm for burning: 
lime. 
Ambra, Ambergris.—Floating on water, without luf¬ 
tre, opake, of a granular texture, foft like wax, and Hack¬ 
ing to the teeth; highly fragrant, without particular tafte; 
melting in the heat of boiling water ; burning eafily with 
a white flame and grey fmoke, and entirely confirming. 
Ambra maritima, or common ambergris : from the ob- 
fervations and conclufions of Dr. Swediaur, it appears be¬ 
yond doubt, that this fubftance is nothing more than the 
excrements of the Phyfeter macrocephalus, or fpertnaceti 
whale, as it is very frequently met with in its inteftines, 
and molt commonly mixed with the beaks of the Sepia 
oftopoda, or cuttle-fifli, which this whale is known to 
feed upon. In a lyftem of Mineralogy, therefore, this 
fubftance is evidently mifplaced. See the article Amber¬ 
grease, vol. i. p. 400. 
Graphites, Black Lead.—Confifting principally of 
carbon, with a little iron, and generally a little lilex or 
alumine: when pure, burns with a reddifli flame, emit¬ 
ting beautiful fparks and a fmeii of fulphur, and leaving- 
little reflduum. Black, opake, very foft; feels fomewhat 
greafy, and ftains the fingers : brittle, breaking into inde¬ 
terminate fragments. Three fpecies are noted, though 
probably they are only varieties. 
1. Graphites plumbago, or common blacklead: ofarne- 
tallic luftre and flaty ftrudture. Found in different parts 
of Great Britain; particularly in Airftiire near Dumfries 
in Scotland, at Borrowdale and Kelwick in Cumberland; 
in Greenland and various parts of the continent. Colour 
blackifli or iron-grey, bluifti-grey when cut, with a flight 
metallic luftre; yields to the impreftlon of the nail, and 
makes a black mark on paper ; texture compact, with a 
fine grain, and rather a little flexible: it is chiefly ufed 
for making black-lead pencils, for blackening ftoves, and, 
when mixed with a proper proportion of filex, for cruci¬ 
bles. Specific gravity, 2; contains, when pure, carbon 
90, iron in. 
This fubftance is by M. Haiiy claffed among the ores,of 
iron. According to its analyfis it correfponds very cloie- 
ly with Kilkenny coal. It is called carburet of iron, from 
its component parts, carbon and iron. It very clolely re¬ 
fembles the metallic ore called fulphuret of molybdenum ; 
. 6 P but. 
M INERALOG Y. 
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