Earths. MINER 
4. Barytes compafta, or compaft heavy fpar: fubopake, 
fliining, of a fplintery frafture, with the fragments inde¬ 
terminate and acutangled. Found in the lead-mines of 
Perbyfhire and Staffordftiire, and in Saxony, in amor¬ 
phous or half-rounded maiTes, or in nodules; breaking 
into ffiarp angular pieces, and when broken has a dull 
appearance, with l'ometimes a little glittering. Colour 
dull grey, yellowilh-white or yellowifh, cream-colour, 
pale flefh-colour, reddifli, or bluiih. Contains fulphat of 
baryt 83*5, filex 67, felenite 2, water 2. 
5. Barytes Bononienfis, or Bologna-ftone: diaphanous, 
lliining, fomewhat fibrous, breaking into fragments more 
or lefs rhombic. Found on the mountain Paterno near 
Bologna, detached in roundilh flat kidney-form pieces, 
the fragments ©f which are obtufangled, roundilh, with 
the fuperficies unequal. Broken in a certain direc¬ 
tion, it appears fibrous; broken in another, it appears 
rather lamellous; fometimes falls to pieces fpontaneoully 
into granular fragments. Colour fmoke-grey, with a 
fmall degree of femi-tranfparency. Contains by analy¬ 
fis fulphat of baryt 62, filex 16, alumine 1475, gyp- 
fum 6, iron 0-25, water 2. Specific gravity, from 4-440 
to 4-496. 
6. Barytes lamellata, or lamellated heavy fpar; fliining 
within, lamellar in a frondofe manner, fpontaneoully 
falling into fcaly fragments 5 the thicker fcales cutting 
the plates under a right angle. Found in the mines of 
Saxony and Tranfylvania, in folid mafles, fometimes in 
Ihiall lenticular cryftals, fometimes cluilered together in 
an oval, kidney, or fpheroid, form. Colour white or cine¬ 
reous, pale yellowilh, or brownifh-red. 
7. Barytes vulgaris, common ponderous fpar, or cawk : 
lamellar, breaking into rhomboid fragments, falling 
fpontaneoully into convergent fcales. Found in various 
parts of Britain and Europe, and is the molt common ma¬ 
trix of metallic ores: it is fometimes found in powder, 
often in amorphous mafles, often cryftallized : it is fome¬ 
times highly polilhed, generally diaphanous, and in its 
cryftallized ftate tranfparent and reflective. Colour fnowy, 
filvery or bluiih, greyilh, greenilh, reddifli, or yellowifh- 
white ; often flelh-colour, fmoke-colour, honey-colour, 
or vinaceous; rarely olive-green, or greenilh or yellowifli- 
grey, or greyilh-black ; very rarely blue : the layers are 
generally ltraight, fometimes incurved. The primitive 
form of its cryftals, according to Haiiy, is a rectangular 
prifm, whofe bafes are rhombs, with angles of 101 0 30' 
and 78® 30'. Contains, by analyfis, pure barytes 67-2, 
fulphuric acid 32-8. Specific gravity, 4-430. 
There is a Angular procefs mentioned by Dr. Lifter, 
which is that of vitrifying antimony by means of cawk. 
This is done with great readinefs and fpeed; and the 
glafs, thus made, will produce fome effect on other me¬ 
tals, which no other glafs will, nor indeed any other pre¬ 
paration of antimony. The method of preparing it is 
this t Take a pound of antimony, flux it clear; have in 
readinefs an ounce or two of cawk in a lamp red hot; put 
it into the crucible to the melted antimony, and continue 
it in fufion; then call it into a clean mortar not greafed, 
decanting the clear liquor from the lump of cawk. This 
procefs gives more than fifteen ounces of glafs of anti¬ 
mony, like polilhed Heel, and bright as the moll refined 
quickfilver. The cawk, in the mean time, is found to be 
diminilhed, not increafed, in its weight, and will never 
flux with the antimony, though ever lo ftrong a fire be 
given it. This is a very odd mineral; and the learned 
author fuppofes it to be allied to thofe white, milky, and 
mineral, juices which are found in mines. The eftedl of 
both is evidently the fame ; for the milky juice of lead- 
mines vitrifies the whole body of antimony, in the fame 
manner that the cawk does in this experiment. Phil. 
1 'vanf. N° 110. 
8. Barytes ftalaftitia, or ftala£lic baryt: of a rounded 
form, or coating other bodies. Found on Mount Iberg 
in Hercynia: of a ftalablical origin and form; in other 
refpetts agreeing with B. vulgaris. 
A L 0 G Y, Earths, 447 
9. Barytes hepaticus, or liver-ilone : colour grey, grey¬ 
ish or yellow-grey ; or brown, or greyilh-black ; fradlurc 
loliated and partly ftriated; fp. grav. 2-666 ; emitting a 
fmell of liver of lulphur when rubbed or heated to red- 
nefs; not eftervefcing with acids. According to the ana¬ 
lyfis of Bergman, a lpecimen from Andraran in Scania 
contains 38 of baro-felenite, 33 of filex, 22 of alum, 7 of 
gypfum, and 5 of mineral oil. Kirwan. 
Crossopetra. —Confiding of ponderous earth, a larger 
portion of filex, and a fmaller of alumine : lightilh, hard, 
parafitic, meagre, cryltalline ; not totally foluble in ful¬ 
phuric acid, even in a boiling heat ; melting with difficulty 
in the fire. There are three fpecies. 
1. Crolfopetra Hercynica, or Hercynian crofs-ftone: in 
four-fided rectangular tables or prifms, tranfverfely ftriate, 
terminating at one end in a needle-point; two of them 
cutting each other croflwife, and longitudinally. Found 
upon calcareous fpar, in the mines of Hercynia, near An- 
drealburg, in fmall aggregate cryftals, fometimes very mi¬ 
nute, rarely pellucid, oftener diaphanous oropake : colour 
milk-white, hyaline, yellowiffi, not always ftriking fire 
. with Heel, yet frequently making a mark upon glafs f 
»melts with borax and foda, with ebullition. 
2. Croflopetra Scotica, or Scotch crofs-ftone: in four- 
fided tables or prifms, one end running into a needle¬ 
point, and not united. Found in the mines of Scotland 
near Strontian ; and diftinguilhed by its larger cryftals. 
3. Crolfopetra ftaurolitis, or ftaurolite : in lix-fided 
prifms, four faces of which are the largeft, meeting in 
pairs, and forming two obtufe angles, meafuring 129®. 
The prifm is either entire or truncated on the obtufe an¬ 
gles. It is not uncommon to find two cryftals penetrating 
each other obliquely, or at right angles, fo as to form a 
crofs; fometimes even three prifms are thus arranged, 
forming a triple crols, whence its name of ftaurolite, which 
fignifies in Greek the fame as crojfopetra in Latin. Its 
furface is fmooth or uneven, and its luftre varies confi- 
derably. Internally it is more or lefs fliining, with a luf¬ 
tre between vitreous and refinous. Its fra6lure, parallel 
to the axis, is imperfectly lamellar; in the oppoiite di¬ 
rection it is fmall-grained, uneven, paffing to conchoidal. 
It is brittle, and fomewhat harder than quartz. Sp. grav. 
3-28. Expofed to the blowpipe, it undergoes no other 
change befides that of fritting a little on its furface. In 
i©o parts, according to an analyfis by Vauquelin, there arc 
33- Silex. 
44- Alumine. 
3-84 Lime. 
13* Oxyd of iron, 
r Oxyd of manganefe. 
5-16 Lois, 
This mineral is found at St. Gothard in Swiflerland, in 
fmall cryftals, imbedded in micaceous fchiftus, aud accom¬ 
panied witlicyanite ; in Brittany, near Quimper, in mid¬ 
dling-fixed cryftals, imbedded in a micaceous clay, appa¬ 
rently produced by the decompofition of fome primitive 
rock ; alfo at St. Jago de Compoftella, in a primitive rock. 
Aikin. 
Order III. CALCAREOUS EARTHS. 
The earths of this order confift principally of carbonat 
of lime; and hence the chief and leading genus is Greta, 
which includes chalk, lime, &c. Of the properties of cal¬ 
careous earths in general, and of lime in particular, we 
have fpoken pretty largely under the article Chemistry, 
vol. iv. p. 222. of the ule of lime and chalk as manure, 
under Husbandry, vol. x. p. 565-7. and of the medi¬ 
cal properties of the preparations of lime, under Lime- 
water, vol. xii. p.719. The following are the generic 
characters. 
Creta. —Confiding of carbonat of lime and carbonic 
acid gas, and a few extraneous fubftances : friable ; ef- 
fervelcing with, and almolt totally foluble in, acids; cal¬ 
cining 
