Z I N 
Z I R 
922 
it in diluted sulphuric or nitric acid, and 
precipitating it by potass. This oxide is used 
as a paint ; but its colour must be perfectly 
white. When zinc happens to contain a little 
iron, which is often the case with the zinc of 
commerce, the oxide obtained has a tinge of 
yellow, because it is mixed with a little yel- 
low oxide of iron. 
The protoxide, or zinc combined with a 
minimum of oxygen, is obtained by exposing 
the peroxide to a strong heat in an earthen- 
ware retort or covered crucible. From the 
experiments of Desormes and Clement, it 
appears that by this process zinc loses a por- 
tion of its oxygen, and assumes a yellow co- 
lour. According to the analysis of these che- 
mists, the protoxide of zinc is composed of 
eighty-eight parts of zinc and twelve parts of 
oxygen. The reduction of the oxides of zinc 
is an operation of difficulty, in consequence 
of the strong affinity which exists between 
ffinc and oxygen. It must be mixed with 
charcoal, and exposed to a strong heat in 
vessels which screen it from the contact of 
t be external air. 
Most of the simple combustibles combine 
with zinc. 
Hydrogen gas dissolves a little of it in cer- 
tain situations. It is usual to procure hydro- 
gen gas by dissolving zinc in diluted sul- 
phuric acid. The gafc thus obtained is as pure 
as any which can be procured. It carries 
along with it however a little zinc in solution ; 
but it deposits it again upon the sides of the 
glass jars, and on the surface of the water 
over which it stands. This gas, if we believe 
the French chemists, contains often a little 
carbureted hydrogen gas ; a proof that zinc 
frequently contains carbon. When this metal 
is dissolved in sulphuric acid, it deposits a 
black insoluble powder, which the French 
chemists found to be carburet of iron. It is 
uncertain whether it is carburet, or carbon I 
combined with zinc, which gives occasion to 
the production of the carbureted hydrogen 
gas. 
It is believed at present that sulphur does 
not combine with zinc in the metallic state ; 
because no attempt to form the combination 
artificially has succeeded. Sulphur unites 
with the oxide of zinc when melted along 
with it in a crucible. This was lirst disco- 
vered by Dehne in 1781. The experiment 
was afterwards repeated by Morveau. The 
sulphureted oxide of zinc is of a dark-brown 
colour, and brittle. It exists native in great 
abundance, and is known by the name of 
blende. Mr. Proust, however, has announced 
it as his opinion, that blende is a sulphuret of 
zinc, or a compound of sulphur and zinc in 
the metallic state. 
Zinc may be combined with phosphorus, 
by dropping small bits of phosphorus into it 
while in a state of fusion. Pelletier, to whom 
we are indebted for the experiment, added 
also a little resin, to prevent the oxidation 
of the zinc. Phosphuret of zinc is of a white 
colour, and metallic splendour, but resembles 
lead more than zinc. It is somewhat malle- 
able. When hammered or filed, it emits the 
odour of- phosphorus. When exposed to a 
strong heat, it burns like zinc.. 
Phosphorus combines also-with the oxide 
of zinc; acompound which Margraf had ob- 
tained during his experiments on phosphorus, 
w hen twelve parts of oxide of zinc, twelve 
parts of phosphoric glass, and two parts of 
5 
Z I N 
charcoal-powder, are distilled in an earthen- 
ware retort, and a strong heat applied, a 
metallic substance sublimes of a silver-white 
colour, which when broken ha? a vitreous ap- 
pearance. This, according to Pelletier, is 
phosphureted oxide of zinc. When heated 
by the blowpipe, the phosphorus burns, and 
leaves behind a glass, transparent while in 
fusion, but opaque after cooling. 
Phosphureted oxide of zinc is obtained also 
when two parts of zinc and one part of phos- 
phorus are distilled in an e-rthen retort. 
The products are, 1. Zinc; 2. Oxide of zinc; 
3. A red sublimate, which is phosphureted 
oxide of zinc ; 4. Needleform crystals of me- 
tallic brilliancy, and a blueish colour. These 
also Pelletier considers as phosphureted oxide 
of zinc. 
Zinc does not combine with azote. Mu 
riatic acid readily converts it into an oxide. 
Zinc combines with almost all the metals, 
and some of its alloys are of great import 
ance. 
It may be united to gold in any proportion 
by fusion. The alloy is the whiter and the 
more brittle, the greater quantity of zinc it 
contains. An alloy, consisting of equal parts 
of these metals, is very hard and white, re- 
ceives a fine polish, and does not tarnish 
readily. It lias therefore been proposed by 
Mr. Malouin as very proper for tiie specula 
of telescopes. One part of zinc is said to de 
stroy the ductility of 100 parts of gold. 
Platinum combines very readily with zinc. 
The alloy is brittle, pretty hard, very fusible, 
of a blueish-white colour, and not so clear as 
that of zinc. 
The alloy of silver and zinc is easily pro 
duced by fusion. It is brittle, and lias not 
been applied to any use. 
Zinc may be combined with mercury, 
either by triturating the two metals together, 
or by dropping mercury into melted zinc. 
This amalgam is solid. It crystallizes when 
melted, and cooled slowly into lamellated 
hexagonal figures, with cavities between 
them. They are composed of one part of 
zinc and two and a half of mercury. It is 
used to rub on electrical machines, in order 
to excite electricity. 
Zinc combines readily with copper, and 
form 1 one of the most useful of all the metal- 
lic alloys. The metals are usually combined 
together by stratifying plates of copper and 
a native oxide of zinc combined with carbonic 
acid, called calamine, and applying heat. 
W hen the zinc does not exceed a fourth 
part of the copper, the alloy is known by the 
name of brass. It is of a beautiful yellow 
colour, more fusible than copper, and not so 
apt to tarnish. It is malleable, and so duc- 
tile that it may be drawn out into wire. Its 
density is greater than the mean. It ought 
to be by calculation 7.6296, but it actually is 
8.3958 ; so that its density is increased by 
about 1-1 0th. When the alloy contains three 
parts ot zinc and four of copper, it assumes a 
colour nearly the same with gold, but it is not 
so malleable as brass. It is then called 
pinchbeck, prince’s metal, or prince Rupert’s 
metal. Brass was known, and very much 
valued, by the antients. They used an ore 
of zinc to form it, which they called cadmia. 
Dr. Watson has proved that it was to brass 
that they gave the name of orichalcum. 
Their o?s was copper, or rather bronze. 
It is very difficult to form an alloy of iron 
and zinc. Wallerius has shewn that iron is 
capable of combining witli a small portion of 
zinc ; and Malouin has shewn that zinc may 
be used instead of tin to cover iron plates, a 
proof that there is an affinity between the 
two metals. 
Tin and zinc may be easily combined by|| 
fusion. The alloy ispnuch harder than zinc,B 
and scarcely less ductile. This alloy is often )• 
the principal ingredient in the compound call-M 
ed pewter. 
The alloy of lead and zinc has been exa-te 
mined by Wallerius, Gelert, Muschenbroeck, f; 
and Gmelin. This last chemist succeeded in f 
forming the alloy by fusion, lie put some a 
suet into the mixture, and covered the cruci-1 
ble in order to prevent the evaporation of the fc 
zinc. When the zinc exceeded the lead very f- 
much, the alloy was malleable, and much a 
harder than lead. A mixture of two parts of I 
zinc and one of lead formed an alloy more a 
ductile and harder than the last. A mixture ’m 
of equal parts of zinc and lead, formed an #; 
altoy differing little in ductility and colour i 
from lead ; but it was harder and more sus- 9 
ceptible of polish, and much more sonorous. 9 
When the mixture contained a smaller quail- I 
tity of zinc, it still approached nearer the l 
ductility and colour of lead ; but it continued | 
harder, more sonorous, and susceptible of] 
polish, till the proportions approached to 1 
pf zinc and 16 of lead, when the alloy differed ! 
from the last metal only in being somewhat 
harder. 
ZINNIA, a genus of plants of the class S) n- 
genesia, order polygamia superflua; and in 
the natural system arranged under the 49th 
order, composita. The receptacle is palea- , 
ceous, the pappus consists of two erect awns, 
the calyx is ovato-cylindrical and imbricated; 
the rays consist of five persisting entire florets. 
There are 5 species, none of them natives of 
Britain. 
ZIRCON. This stone is brought from 
Ceylon, and found also pi France and Spain, 
and other parts of Europe. It is commonly . 
crystallized. The primitive form of its crys- 
tals is an octahedron, composed of two four- 
sided pyramids applied base to base, whose 
sides are isosceles triangles. The inclination 
ot the sides of the same pyramid to each other 
is 124° 12'; the inclination of the sides of one 
pyramid to those of another 82° 50'. The so- 
lid angle at the apex is 73° 44'. The varieties 
of the crystalline forms of zircon amount to 
seven. I 11 some cases there is a four-sided 
prism interposed between the pyramids of the 
primitive form; sometimes all the angles of 
this prism are wanting, and two small trian- 
gular faces in place of each; sometimes the 
crystals are dodecahedrons, composed of a flat 
four-sided prism with hexagonal faces, termi- 
nated by four-sided summits with rhomboidal 
faces ; sometimes the edges of this prism, 
sometimes the edges where the prism and sum- 
mit join, and sometimes both together, are 
wanting, and we find small faces in their place. 
Tor an accurate description and figure of these 
varieties, the reader is referred to Hauy. 
The texture of zircon is foliated. Frac- 
ture imperfectly conchoids]. Causes a very 
great double refraction. Specific gravity 
from 4.615 to 4.383. Colours various, corn- j 
monly reddish or yellowish ; sometimes it is ; 
limpid. Before tiie blowpipe it loses its to- 1 
lour, but not its transparency. With borax 
