221 
C H E M I S TRY. 
Sit-EX.—This ear.th is never found pure. To obtain 
it, therefore, reduce tranfparent cryftals of quartz to 
powder; put them into a crucible with four parts of pot- 
afh, and increafe the fire till the mixture melts. Then 
diflolve it in diftilled water; add fulphuric acid, which 
attacks the potafh, and the fiiex is precipitated ; wafh.it 
in waters till the laft water -remains infipid. It is necef- 
ary to put an excels of acid, to feparate all other earths 
from the fiiex. Another method of obtaining it very- 
pure, is by feparating it from fluoric acid, as defcribed 
under that article. 
Many Hones contain fiiex in great quantity, as rock- 
cryltal, flint, jafper, agate, grit-ltone, &c. as (hewn in 
the works of Kirwan, Bergman, Buffon, Daubenton, 
Pott, Bucquet, Fourcroy, De Born, See. —Pure fiiex has 
an extraordinary roughnefs and afperity to the touch. 
It is free from vifeofity, audits molecules when foaked 
in water are precipitated with great eafe. It has neither 
tafte nor fmell; it is always^ tranfparent in its very laft 
articles. Its fpecific gravity is It cannot alone 
e fufed in fire; but may be melted with the addition of 
borax and alkalis ; the blow-pipe will not meit it. Air 
makes no change in it. It cannot be difl'olved in water 
by chemical methods: it ablbrbs part of it; flicks round 
it, and takes a regular form : this is rock-cryftal. It will 
unite with the phofphoric, boracic, and fluoric, acids: 
by fufion, a coloured glafs is, produced. Muriatic acid 
holds it in fufpenfion ; but, as foon as the acid is warmed, 
the fiiex is precipitated. Other acids have no efrebt up¬ 
on fiiex. 
Alumine.—T his name has been appropriated to this 
fubftance, becaufe it conftitutes the bale of alum: fome 
authors call it argil, or argillaceous earth : it is never 
found pure: it is procured in abundance from all kinds 
of clay, potters’ earth,.fchiftufes, fteatites, the ruby, fap- 
phire, Sc c. 
To obtain pure alumine, melt common alum, or acid 
fulphat of alumine, in water; add a folution of potalh, 
or carbonat of potalh, or rather liquid ammoniac : a 
plentiful white precipitate, will be the refult. Heat the 
mixture a little. Ammoniac is preferred, becaufe it has 
not the property, like the other alkalis, to re-diffolve 
the alumine, if too plentiful. Strain the liquor, and a 
white mafs remains, which mult be walked feveral times, 
to leparate all the faline matters it may retain. 
Alumine is white, opaque, foft to the touch, taftelefs, 
bur adhenve to the tongue. It dries in the fire, con¬ 
tracts into a lefs volume than in its natural ftate, and be¬ 
comes fo hard as to ftrike fire with fleel. This property 
of diminution, or extreme aggregation, when expol'ed to 
the adtion of heat, has cauled it to be uled by Wedge- 
wood to conftruft his pyrometrical inftruments, for.mea- 
furing the expanlion of bodies by heat. After it has 
been well baked, it is no longer capable of being knead¬ 
ed in water into a dubtile mafs. Lavoilier has proved, 
that pure alumine is fufceptible of a kind of tenacious fu¬ 
fion by a current of oxygen ; after which it will cut 
glafs like a diamond, and is hardly to be touched by a file. 
It abforbs humidity from the atmofpbere, and a little 
carbonic apid. Alumine makes a paite with water, and 
may be kneaded very ealily. It becomes very hard by 
mixture with water and fiiex. It is employed in many of 
the arts ; it forms the bafes of potteries, from bricks to 
the fineft porcelain. Its exabt nature is unknown. 
Glucine.—V auquelin is the dilcoverer of this earth, 
and he called it earth of beryl, becaufe he firft found it in 
the beryl ; he found it alfo in tire emerald of Peru. To 
ext raft it, take beryl reduced to powder; melt this pow¬ 
der in cauftic potalh, and diflolve the produft in muri¬ 
atic acid. Separate the fiiex by evaporation ; and, hav¬ 
ing walhed it, decompofe the remaining liquor with the 
potalh of commerce; walh the depofit, and diflolve it 
again in fulphuric acid ; by adding fulphat of potalh to 
this folution, alum is produced. As the combination 
of this earth does not cryftallize fo eafily as alum, it re- 
Vol. IV. No. 191, 
mains in the clear water! to feparate it entirely from the 
laft remains of the alum, decompofe this water with an 
excefs of carbonat of ammoniac ; the earth is hereby dif- 
folved again, and the alumine is precipitated. Then, 
evaporating the carbonat of ammoniac by means of heat, 
the new earth is depofited in the ftate of carbonat; the 
quantity obtained is fixteen in 100 of the beryl made ule 
of. Its name, glucine, is from the Greek Xyvy.m;, Iweet, 
on account of its molt charafteriftic property of forming 
faccharine falts with acids. 
This earth is white, infipid, infoluble in water, adher¬ 
ing to the tongue ; infufible per fe. Soluble in fixed al¬ 
kalis ; infoluble in ammoniac, but foluble in carbonat 
of ammoniac. Soluble in moift acids, except the carbo¬ 
nic and phofphoric, and forming with them faccharine 
falts flightly aftringent. It is very foluble in the fulphu¬ 
ric acid by excefs. It is fufible in boriax, forming with 
it .a tranfparent glafs. It abforbs one fourth of its weight 
of carbonic acid; decompofes aluminous falts; is not 
precipitated by hydro-fulphures well faturated. 
It is not yet known of what ufe this earth may be in 
the arts. If it fli'ould be found more plentiful hereafter, 
fays Vauquelin, in combinations from which it might 
be more eafily obtained, it may be applied to many ufe- 
ful purpofes in the arts, in chemiftry, and in medicine. 
It has already been remarked to have a ftrong affinity for 
animal and vegetable fubftances ; fo that it very probably 
might ferve, like alumine, as a cauftic in dying. The 
faccharine and fiightly-aftringent tafte of its laline com¬ 
binations, leave little room to doubt but it muft poffefs 
fome valuable properties as a medicine ; and it certainly 
would prove the moft agreeable phyfic that could be taken, 
on account of its grateful tafte. 
Zircone, C[rcon, or Jargon. —Klaproth firft dis¬ 
covered this earth in the zircon or jargon of Ceylon, and 
afterwards in the hyacinth, as a predominant principle 
and peculiar fpecies of earth. 
To extraft this earth, take hyacinths of Ceylon well 
pulverized ; mix them with eight ermine parts of alkali; 
put the mixture into a red-hot crucible, a fpoonful at a 
time, fullering each fpoonful to melt before another is 
put in. When the whole is in fufion, make the lire very 
ftrong, and keep it fo for an hour and a halt, or more, 
according to the quantiiy of matter in fufion. After¬ 
wards let the crucible get cold, break it, reduce the con¬ 
tents to powder, which boil in fpring-water in a leaden 
veffel: let it fettle ; decant the clear liquor, and conti¬ 
nue thus to walh the earth, till the water uled no longer 
produces any precipitation in a folution oi muriat of 
barytes. The mafs, thus purified, is to be diluted with 
twenty pints of water; and pour in pure muriatic acid 
till there is an excels ienfible to the tafte ; boil thefe fub- 
ftances for a quarter of an hour, in a leaden veffel. When 
the folution is finilhed, ftrain off the liquor, and eva¬ 
porate to’drynefs, in veffels of the fame kind, to feparate 
the portions of fiiex which the.muriatic acid may have 
difl'olved. The fait is to be diffolved once more in wa¬ 
ter ; filtre again, and the zircone is precipitated with 
lire carbonat of foda. Then the zircone is found com¬ 
ined with carbonic acid, which in drying becomes 
brighter than pure zircone. 
This earth calcined is of a white colour, very heavy, 
rough to the touch like fiiex, taftelefs, not foluble in wa¬ 
ter, but forming a kind of jelly therewith. Of itfelf, 
it is not to be melted by the blow-pipe; but with borax 
it melts into a tranfparent colourlefs glafs. Separated 
from its folutions - by cauftic alkalis, it retains, as it 
dries in the air, a great quantity of water, which gives it 
a tranfparency, and the appearance of gum arabic, 
flightly yellow, and exhibiting even the fame vitreous 
cracks: the water increafes its weight about one fourth 
part. Urged now by a ftrong heat, it will melt, and af-' 
fume a faint grey colour; it thereby acquires fuch a de¬ 
gree of hardnefs, that it will ftrike fire with fteel, and 
leratch the hardeft glafs. It unites with acids, and forms 
3 L ' 
