0/0 S I L 
Silver melts when it is heated completely red 
hot; and while melted, its brilliancy is much 
increased. According to the calculation of 
Bergman and Mortimer, its fusing point is 
1 000° of Fahrenheit. It continues melted at 
23° Wedgewood. but requires a greater heat 
to bring it to fusion. Ifthe heat is increased 
after the silver is melted, the liquid metal 
boils, and may be volatilized; but a very 
strong and long-continued heat is necessary. 
When cooled slowly, its surface exhibits 
the appearance of crystals; and if the liquid 
part of the metal is poured out as soon as the 
surface congeals, pretty large crystals of sil- 
ver may be obtained. By this method Tillet, 
and Mongez junior, obtained it in four-sided 
pyramids, both insulated and in groups. 
_ Silver is not oxidated by exposure to the 
air: it gradually, indeed, loses its lustre, and 
becomes tarnished; bat this is owing to a dif- 
ferent cause. Neither is it altered by being 
kept under water. But if it is kept for a long 
time melted in an open vessel, it gradually 
attracts the oxygen from the atmosphere, and 
is converted into an oxide. Macquer, by- 
exposing silver 20 times successively to the 
heat of a porcelain furnace, obtained a glass 
of an olive-green colour. Nay, ifthe heat is 
sufficient, the silver even takes fire and burns 
like other combustible bodies. Van Marum 
made electric sparks from his powerful Tey- 
lerian machine pass through a silver wire; 
the wire exhibited a greenish-white flame, and 
was dissipated into smoke. Before a stream 
of oxygen and hydrogen gas, it burns rapidly 
with a light-green flame. 
The oxide of silver, obtained by means of 
heat, is of a greenish or yellowish grey co- 
lour; and is easily decomposed by the appli- 
cation of heat in cloEe vessels, or even by ex- 
posing it to the light. When silver is dis- 
solved in nitric acid, and precipitated by lime 
water, it falls to the bottom under the form of 
a powder, of a dark-greenish brown colour. 
Prom the experiments of Wenzel and Berg- 
man it follows, that the greenish or yellowish 
grey oxide is composed of about 90 parts of 
silver and 10 of oxygen. When this oxide is 
exposed to the light, part of its oxygen is se- 
parated, as Scheele first ascertained ; and is 
converted into a black powder, which contains 
but a very small portion of oxygen, and may 
be considered as silver reduced. By expos- 
ing the solution of silver in nitric acid to sun- 
shine, the silver precipitates in the form of a 
ilea-brown powder. 
Neither carbon nor hydrogen has been 
combined with silver; but it combines rea- 
dily with sulphur and phosphorus. 
1. When thin plates of silver and sulphur 
are laid alternately above each other in a cru- 
cible, they melt readily in a low red heat, and 
ferin sulphuret of silver. It is of a bk ck or 
very deep violet colour ; brittle, but capable 
of being cut with a knife; often crystallized 
in small needles; and much more fusible than 
silver. If sufficient heat is applied, the sul- 
phur is slowly volatilized, and the metal re- 
mains behind in a state of purity. It is very 
difficult to determine the proportion of the 
ingredients which enter into the composition 
of this substance, because there is an affinity 
between silver and its sulphuret, which dis- 
poses them to combine together. The great- 
est quantity of sulphur which a given quan- 
S I L 
tity of silver is capable of taking up, is, ac- 
cording to Wenzel, 
It is well known, that when silver is long 
exposed to the air, especially in frequented 
places, as churches, theatres, &c. it acquires 
a covering of a violet colour, which deprives 
it ot its lustre and malleability. This cover- 
ing, which forms a thin layer, can only be de- 
tached from the silver by bending it, or break- 
ing it in pieces with a hammer. It was ex- 
amined by Mr. Proust, and found to be sul- 
phuret of silver. 
2. Silver was first combined with phospho- 
rus by Mr. Pelletier. If one ounce of silver, 
one ounce of phosphoric glass, and two 
drams of charcoal, are mixed together, and 
heated in a crucible, phospliuret of sulphur is 
formed. It is of a white colour, and appears 
granulated, or crystallized. It breaks under 
the hammer, but may be cut with a knife. It 
is composed of four parts of silver and one of 
phosphorus. Heat decomposes it by sepa- 
rating the phosphorus. Pelletier has'observ- 
ed, that silver in fusion is capable of combin- 
ing with more phosphorus than solid silver: 
for when phospliuret of silver is formed by 
projecting phosphorus into melted silver, af- 
ter the crucible is taken from the fire, a quan- 
tity of phosphorus is emitted the moment the 
metal congeals. 
Silver does not combine with the simple 
incombustibles. 
Silver combines readily with the greater 
number of metallic bodies. 
1. When silver and gold are kept melted 
together, they combine, and form an alloy 
composed, as Homberg ascertained, of one 
part of silver, and five of gold. He kept 
equal parts of gold and silver in gentle fusion 
for a quarter of an hour, and found, on break- 
ing the crucible, two masses, the uppermost 
of which was pure silver, the undermost the 
whole gold combined with ± of silver. Sil- 
ver, however, may be melted with gold in 
almost any proportion; and ifthe proper pre- 
cautions are employed, the two metals remain 
combined together. 
The alloy of gold and silver is harder and 
more sonorous than gold. Its hardness is a 
maximum when the alloy contains two parts 
of gold and one of silver. The density of 
these metals is but little increased; but the 
colour of the gold is much altered, even when 
the proportion of the silver is small ; one part 
of silver produces a sensible whiteness in 
twenty parts of gold. The colour is not only 
pale, but it has also a very sensible greenish 
tinge, as if the light reflected by the silver 
passed through a very thin covering of gold. 
This alloy being more fusible than gold, is 
employed to solder pieces of that metal toge- 
ther. 
2. When silver and platinum are fused to- 
gether (for which a very strong heat is neces- 
sary), they form a mixture, not so ductile as 
silver, but harder and less white. The two 
metals are separated by keeping them for 
some time in the state of fusion; the plati- 
num sinking to the bottom from its weight. 
This circumstance would induce us to sup- 
pose that there is very little affinity between 
them. 
The affinities of silver, and its oxides, 
are placed by Bergman in the follqwing or- 
der : 
8 1 t 
fhLfER, 
Oxide o? SitVSle# 
Lead, 
Muriatic acid. 
Copper, 
CNalic, 
Mercury, 
Sulphuric, 
Bismuth, 
Saclactic, 
Tin, 
Phosphoric, 
Gold, 
Sulphurous, 
Antimony, 
Nitric, 
Iron, 
Arsenic, 
Manganese, 
Fiuoric, 
Zinc, 
Tartaric, 
Arsenic, 
Citric, 
Nickel, 
Lactic, 
Platinum, 
Acetic, 
Sulphur, 
Succinic, 
Phosphorus. 
Prussic, 
Carbonie. 
Silver, fulminating. See Fuxmijja> 
xion. 
Sxlver-lea.f, that beaten out into fine 
leaves for the use of the gilders, which is per- 
formed in the same manner as gold-leaf. 
Silver-wire , that drawn out into fine 
wire; for the manner of doing which, see the 
articles Gold-wire, and Wire-drawing. 
SrLVER, shell, is prepared of the shreds 
of silver-leaves, or of the leaves themselves, 
for the use of painters, after the same manner 
as shell-gold. See Gold. 
Silvering. The art of silvering wood, 
paper, &c. is performed in the same maimer 
as gilding, making use of silver instead of gold 
leaf. 
To silver copper or brass, clean the metal 
with aqua fortis, by washing it lightly, and 
then throwing it in water; or by scouring it 
with salt and tartar with a wire brush. Dis- 
solve some silver in aqua fortis, and put 
pieces of copper into the solution ; this will 
throw down the silver in a state of metallic 
powder. Take 20 grains of tills powder, and 
mix with it two drams of taytar, the same 
quantity of common salt, and half a drachm of 
alum ; rub the articles with this composition 
till they are perfectly white, then brush it off; 
and polish them with leather. 
To silver the dial-plates of clocks, scales 
of barometers, dfc. Take half an ounce of 
silver lace, add to it an ounce of double-re- 
fined aqua fortis, put them into an earthen 
pot, and place them over a gentle fire till all is 
dissolved, which will happen in about five 
minutes ; then take them off, and mix it in a 
pint of clear water, after which, pour it into 
another clean vessel, to free it from grit or se- 
diment; then add a spoonful of common salt ; 
and the acid, which has now a green tinge, 
will immediately let go the silver particles, 
which form themselves into a white curd; 
pour oft' the acid, and mix the curd with two 
ounces of salt of tartar, half an ounce of 
whiting, and a large spoonful of salt, more or 
less, according as -you find it for strength. 
Mix it well up together, and it is ready°fo» 
use. 
Having well cleared the brass from scratch- 
es, rub it over with a piece of old hat and 
rottenstone, to clear it from all greasiness, 
and then rub it with sail: and water with your 
hand: take a little of the beforementioned 
composition on your finger, and rub it over 
where the salt has touched, and it will adhere 
to the brass, and completely silver it. After 
£ which, wash it well with water, to take ytf 
