446 Earths.' M' I N E R 
Marazion, in Cornwall. The colouring matter of cryftal- 
Mzed aCHnolite appears, from the analyfis of Langier, to 
be chrome. The hexahedral prifms are commonly of a 
beautiful green, imbedded in white talc. AClinolite oc¬ 
curs at Glenelg in Invernefsfhire, and in the ifle of Sky; 
and, dilfeminated in trap, in Shropfliire. 
Hornblenda. —Confiding of carbonat of magnefia, an 
equal portion of oxyd of iron, and nearly an equal quan¬ 
tity of carbonat of lime: foft, opake, generally of a dull 
colour, leaving a ftreak, lamellous, breaking into indeter¬ 
minate fragments: melting in the fire, with ebullition, 
into a black opake globule. There are three fpecies. 
x. Hornblenda vulgaris, or common hornblende: with 
hardly any luftre, of a dull colour when broken in any 
direction, and exhibiting lamellar pieces or rays. Found 
in Sweden, Saxony, Portugal, Bohemia, and mod Eu¬ 
ropean mountains, in folid maffes, interfperfed with other 
dones; fometimes crydallized in fix or eight fided prifms : 
it is always either radiated or foliated, and the crydals 
are tranfverfely driated. Colour dull green or blackilh: 
fraCture ltraight or curved, or divergingiy ftriate. Con¬ 
tains filex 37, alumine 27, iron 25, lime 5, magnefia 3. 
jT/tomfon. 
2. Hornblenda Labradorica, or Labrador hornblende : 
fubopake, with a little ludre, in curved lamellar pieces, 
which when broken difcovers a coppery-black internal 
furface. Found in fcattered pieces in the idand of St. 
Paul, on the Labrador coad. Colour greyifh-black, with 
fometimes a diade of coppery-red or iron-grey, according 
to the direction of the light: fraCture modly curved and 
foliated. 
3. Hornblendabafaltina,or bafaltic hornblende: fhining, 
hardifh, leaving a greyifh-white dreak ; when broken lon¬ 
gitudinally exhibiting draight lamellar pieces, crydalliz- 
ing into fix or eight fided prifms, terminated by three- 
ffded pyramids. Found in bafalt, tuffe, wacke, and lavas, 
in mod parts of Europe, to which it adheres very clofely. 
Colour black, greenifli-black, dark-green, or yellowifh- 
green ; of a fhining furface when broken : melts before 
the blow-pipe into a greyifh enamel with a tinge of yel¬ 
low. Contains filex 58, alumine 27, iron 9, lime 4, mag¬ 
nefia 1. Bergman. 
( 3 . Augite, the Silex augites of Werner, pyroxene of 
Haiiy, is laid to be a variety of bafaltic hornblende. Co¬ 
lour olive-green, black, white, or grey. It is found fome¬ 
times in rounded pieces, and in grains, but mod fre¬ 
quently crydallized. The primitive form is an oblique- 
angled prilm, the bafes of which are rhombs; the form 
of the crydals is generally a fix and eight fided prifm, 
terminated by a two-fided fummit. The crydals are com¬ 
monly fmall, fmooth, and brilliant, fometimes a little 
fhining. Internal ludre diining, and almod refplendent; 
refinous. FraCture perfectly foliated; cleavage double; 
tranflucent at the edges ; harder than olivine ; gives lively 
fparks with deel, and fcratches glafs; rather brittle. Spe¬ 
cific gravity 3-226 to 3-777. It is fufible before the blow¬ 
pipe with difficulty, and only in fmall fragments, which 
melt into a black enamel. Different fpecimens produced 
as follows: 
From Astna, 
\ 3UGUclin« 
From Arendal, Roux. 
Silex 
5 2 
45 
Lime 
13-20 
3°’5 
Alumine 
333 
3 
Magnefia 
Oxyd of iron 
10 
14*6.6 
l6 
Oxyd of manganefe 
2 
5 
Lois 
4-8 X 
•5 
100*00 
100*0 
Augite is found in bafalt along with olivine and horn¬ 
blende, in Bohemia, Hungary, and Tranfylvania; and in 
the bafalt of Arthur’s Seat, near Edinburgh. Brcchant , 
i. 179. 
ALOG Y. Earths. 
For the remaining genera of this and the following 
claffes and orders, not noticed here, fee each particular 
article under its proper head; as Talcum, Serpen-*- 
tinus, &c. 
Order II. PONDEROUS EARTHS. 
The chief and leading genus in this order is Barytes, 
or “ ponderous earth” more particularly fo called. The 
Englidi and French names of this earth are derived from 
the Greek ( 3 a^vc, heavy, on account of the high fpecific 
gravity of the ponderous fpar, or native fulphat of barytes, 
which is the commoneft form in which this earth appears. 
It is toScheelethat we are indebted for the difcovery of this 
fubftance, in 1774. In his valuable eflay on manganefe, 
he informs us, that the nitric and muriatic folutions pre¬ 
pared from the native black oxyd of that metal contain, 
befides, an earth differing from all thofe hitherto known 
by its ftrong affinity for fulphuric acid, &c. In 1775, 
Galhn made his analyfis of the ponderous fpar, and found 
it to confifl of the earth newly difcovered by Scheele, and 
the fulphuric acid. Bergman repeated and confirmed the 
experiments of thefe chemilts, and named the earth terra 
ponderofa. Morveau propofed the term barotc, derived 
from the Greek, which Mr. Kirwan foftened into barytes. 
In this appellation Bergman acquiefced; and it is now 
adopted by all except the German chemifts, who, in 
conformity with their general cuftom, prefer the term 
fchrvererde, which is a literal tranflation in their own lan¬ 
guage of heavy earth. Weigleb and Afzelius contributed 
to enlarge our acquaintance with this fubftance; and, in 
1793, Dr. Hope publifhed his valuable experiments in the 
Edinburgh TranfaCtions. In 1796, Klaproth augmented 
our know-ledge by his mafterly analyfis of the native lul- 
phats and carbonats of barytes; and, in 1797, Pelletier 
and Vauquelin gave to the world their able memoirs, 
confirming the faCts already admitted, and adding to them 
many new ones. 
We have noticed the general properties of this genus 
under the article Barytes, vol.ii. and Chemistry, vol. iv. 
It remains to enumerate the generic characters, and to 
give a brief defcription of the fpecies. 
Barytes. —Generic characters: It confifts almoft en¬ 
tirely of ponderous earth; is ponderous, parafitic, very 
brittle, harfh to the touch, foft: entirely foluble in boil¬ 
ing fulphuric acid; in the fire at firft deprived of the co- 
hefion of its parts, and afterwards melting without ebul¬ 
lition. There are eight fpecies, in tw-o divifions. 
1. Combined with carbonic acid gas, which does not 
totally difengage itfelf during liquefaction, and therefore 
effervefcing with acids. 1. Barytes Witheringii, baryt, or 
Witherite. Specific character, of a common figure and 
equal texture. Found at Anglezark near Chorley in Lan- 
cafhire, near St. Afaph in Wales, and in Argyleftiire in 
Scotland, in folid maftes, and cryftailized. Texture fhining, 
radiated, fibrous: colour greenifli-white or white: cryf- 
tals fmall fix-fided prifms terminated by fix-fided pyra¬ 
mids -. w-lien heated, it becomes opake. Its pow-der phof- 
phorefces when thrown on burning coals. Contains baryt 
62, carbonic acid 22, water 16. 
2. Barytes lamellofa, or lamellar baryt: lamellar, of a 
cryftalline figure, femi-pellucid, fmooth on the outer fur¬ 
face, fhining within. Varies with four and fix fided prifms. 
Found in Scotland, Lancafhire, Yorkfhire, and Saxony, in 
folid maffes -. colour white, with a degree of tranfparency. 
II. Saturated with fulphuric acid, and therefore not 
effervefcing with acids ; fliining in the dark, after having 
been w-hitened in the fire. 3. Barytes terreftris, or earthy 
fulphat of baryt: friable, in an earthy loofe or united 
form. Found in the lead-mines of Stafford and Derby, 
near Freyburg, and in the vicinity of Paris, in coarle dufty 
particles, molily forming fmall concretions, feldom in 
the form of powder: has an arid appearance; feels coarfe, 
rough, and harfh, and foils the fingers a little: colour 
fnow-white, greyilh, reddifh, or yellowifh-white. 
z 4. Barytes 
