505 
variable proportion of carbon, which modifies its hard- 
nefs and malleability, i'o that, when fully charged with 
this fubftance, (though pure in every other refpedt,) it is 
almoft brittle. 
The combined influence of the air and moifture, at the 
common temperature* has no effedt on nickel; but, when 
expofed to the air at a red heat, it becomes brittle, of 
a blackifh-brovvn-colour externally, and, when pulverifed, 
appears greenifli; its weight is augmented by about 5 per 
cent, but it ftill remains as attradfable by the magnet as 
at firft, and diffolves- in nitric acid with a copious dilen- 
gagement of nitrous gas. In. this ftate it appears to be a 
mixture of metallic and oxydifed nickel; the.latter of 
which, adhering to the furface of the fmall grains of the 
former, prevent them from being added on by the air. 
Ann. de Chimie. 
Zincum, Zink.—Generic charaflers: Brilliant white 
with a fliade of blue : hardilh, a little malleable, but not 
dudfile, flightly fonorous, of a fibrous or fcaly texture ; 
fpecific gravity, 7-12 : burning with a brilliant white flame 
when heated to a ltrong degree, and emitting light white 
flakes ; when fufed with copper, giving.it a brafly-yellow 
colour: eafily foluble in acids, imparting no colour to 
the lolution, but depriving it of its. acrimony. There 
are eight fpecies or combinations of zink. 
1. Zincum ocliraceum, loofe or friable zink: powdery, 
white, without luftre. Found in China, Sweden, and 
Carinthia; and uled in the formation of the metal called 
tutenag. 
2. Zincum calciforme, or zink-ore : compact, very foft, 
opake, white, without luftre. Found near Workfworth ; 
and in Siberia, Sweden, Bohemia, Auftria, See. of an earthy 
or minutely-lamellar form internally, fometimes cellular, 
nodular, fiitular, or yarioufiy imitative. Colour white, 
fometimes verging to yellow or grey. It effervefees with 
acids, in which it is almoft totally dilTol.ved. 
3. Zincum vitreum, or carbonat of zink: hard, tranf- 
parent, of a glafly luftre. Many mineralogifts do not 
admit this as a diftindt fpecies ; and all allow that in ex¬ 
ternal charadters it very cloiely refembles the native oxyd, 
or calamine. It is found in Derbyftiire and Somerfetfhire, 
Carinthia and Siberia, fometimes in folid malfes, fome¬ 
times ftaladlitical or cryftallized : colour grey, with often 
a tinge of blue, green, or yellow; it contains oxyd of 
zink 65-2, carbonic acid 35-2. 
4. Zincum liliceum, or flinty zink: white, fibrous, fe- 
parating into concentric concretions, glatinizing with 
acids. Found at Wanlock-liead in Scotland ; and differs 
from calamine in containing frequently one-third part of 
filex. All the fpecies which contain fllex are more or lefs 
eledfric by heat. 
5. Zincum lpatofum, or zink-fpar: lamellar, diapha¬ 
nous; decrepitating iomewhat before the blowpipe, but 
not emitting fulphurous vapours; of a common or glo¬ 
bular form. Found in Nottinghamlhire ; and in Auftria, 
Carinthia, &c. Colour white, with often a mixture of 
greenilh, yellowitli, reddilh, or blackilh. It always con¬ 
tains fome lilex, but not in fucli abundance as to caule 
it to ftrike fire with fteel. 
6. Zincum cryftallinum, or cryftallized zink-fpar: la¬ 
mellar, diaphanous; decrepitating fomewhat before the 
blowpipe, but not emitting fulphurous vapours; of a 
cryftalline form. Found with the preceding, of which it 
is only a cryftallized variety. The cryftals are fometimes 
diftindt, but oftener confufed, jn rhomboidal four-fided 
prifms or redtangular four or ftx ftded plates, or prifms 
or pyramids varioufly modified. 
7. Zincum calaminaris, calamine, or oxyd of zink: 
foft, tinged with fome colour; of a common form and 
earthy texture, opake, without luftre, totally foluble in 
nitric acid. Found in . various parts of Great Britain; 
and in New Spain, Poland, Siiefia, Saxony, Bohemia, 
Auftria, &c. maflive, diffeminated, or varioufly imitative. 
Colour greyilh, greenifli, yellowilh, reddilh, or brownilh: 
fradture earthy, fometimes fplintery, rarely conchoidul; 
Metals. 
before the blowpipe it decrepitates, but does not melt, 
and fometimes effervefees with acids. Specific gravity, 
3'434 to 4 - 1. Combined with copper, it forms feverai ufe- 
ful alloys: when the zink does not exceed a fourth part 
of the copper, it makes brals, and becomes malleable and 
dudtile : when three parts of zink are combined with four 
of copper, it then forms pinchbeck, or prince’s metal, of 
a deeper orange-colour than brafs, and not I'o malleable. 
Cryftallized oxyd of zink, which is frequently met with 
in Somerfetlhire, Derbyftiire, and Nottinghamlhire, is dif- 
tinguiftied from many of thofe fubftances called zeolites, 
in not fwelling up into a fpongy mafs upon the applica¬ 
tion of the blowpipe: from carbonat of lime, by either 
not effervefeing with nitric acid, or by becoming gelati¬ 
nous when dift'oived in it: from fulphat of lime and ful- 
phat of barytes, by its folubility in acids. When cryftal¬ 
lized it eafily becomes ele&ric by heat, and retains its 
eledlricity for fome hours. 
A Angular form of oxyd of zink has lately occurred in 
thofe mines in Sweden which produce the grey ore of 
copper called faldertz. It is principally a combination 
of oxyd of zink with alumine : its fpecific gravity is 4-66 ; 
and it is fufficiently hard to fcratch glafs. It is met with 
in oftohedral cryftals of an iron-grey colour, imbedded 
in a rock of the nature of compaft talc. It is called 
automnlite, or automolite. 
8. Zincum pfeudogalena, blende, black-jack, or firl- 
phuret of zink : with a femi-metallic luftre, of a lamellar 
texture, emitting fulphurous flame or vapour before the 
blowpipe. There are three varieties of blende; yellow, 
brown, and black. Found in various parts of Great Bri¬ 
tain, Siberia, Norway, Sweden, Germany, Hungary, &c. 
in various drapes and mixtures. When mixed with lead, 
it forms the metal called tutenag; and, combined with 
tin, it is an ingredient in pewter. We may add, that 
blende fometimes becomes pholphorefcent by fridtion in 
the dark; and, according to Bergman, emits light as 
powerfully under water as in the air. The caufe of the 
phofpliorefcence of blende is not known : it is fometimes 
excited by the flighted force. 
Siilphuret of. zink is one of the moft common metallic 
ores ; its matrix is very frequently quartz and carbonat 
or fluat of lime. When roafted, in order to expel the 
fulphur, it is uled inftead of calamine in brafs-making. 
It almoft always accompanies galena; which it fometimes 
fo clofely refembles, that, though the two fubftances are 
placed by each other’s fide, the eye can fcarcely difeern 
the difference: lrence the name of pfeudogalena. Sul- 
phuret of zink may be diftinguilhed from moft other fub¬ 
ftances which it reiembles by exhaling a fulphurous odour, 
like that from Harrowgate-water, when either triturated 
in a mortar or thrown into an acid. 
Palladium. —This metal and the three following were 
difeovered in Platinum, and have been briefly noticed in 
the defeription of that metal, p. 479. 
Dr. Wollafton gives the following procefs for feparating 
and procuring Palladium. The grains of platinum, as 
they come from South America, are firft to be roafted, to 
diilipate the mercury, and then digefted in weak nitro- 
muriatic acid, to feparate the gold, and other metals of 
eaiy folubility. The remainder is now to be digefted in 
a fand-bath, with ftrong nitro-muriatic acid. The whole 
will be diffolved, with the exception of a black fcaly pow¬ 
der, from which the metals Iridium and Olinium are ob¬ 
tained. The folution contains platinum, rhodium, and 
palladium, with perhaps other metals. The platinum is 
firft to be precipitated by a folution of muriat of ammbnia. 
Into the remaining folution immerfe a clean piece of zink, 
which precipitates the palladium and rhodium in their 
metallic forms, with the other metals that may be pre- 
fetit. This refiduum is next to be digefted, with weak 
nitric acid, in the cold, in order to dilfolve any eaiily- 
oxydable metal that may be prelent. The’ remainder, 
being walhed with diftilled water, is now to be dift'oived 
in nitro-muriatic acid. To this folution fome muriat of 
foda 
Metals. M INERALOGY. 
