344 
psr-mine perhaps known, is that at the Paris 
mountain, in the isle of Anglesea. 
Pare copper is ot a red colour, very tena- 
cious, ductile, and malleable. It melts at 27 
degrees ot Wedge wood's pyrometer, and 
burns with a green flame. When heated in 
contact with air, it is changed into a blackish 
red oxyd, which by a more violent heat is 
converted into a brown glass. The nitric' 
acid dissolves copper with effervescence, and 
the .solution has a blue colour. The acid 
lirst oxydates the metal ; a large quantity of 
nitrous gas is then disengaged, and the cop- 
per afterwards dissolves. This is nitrate of 
copper. The sulphuric acid does not dis- 
solve copper, unless when concentrated ; and 
very (me blue crystals, known under the 
name of sulphate of copper, are the result, 
d his is what is commonly called blue vitriol. 
I he muriatic acid does not dissolve copper, 
but when concentrated, and in a state of 
ebullition ; the solution is green, the taste of 
which is caustic, and exceedingly astringent. 
The acetous- acid, in a sufficient degree of 
concentration, dissolves copper; but when 
not sufficiently concentrated, it only imper- 
fectly oxydates it, forming verdigris; which, 
being dissolved in vinegar, forms crystallised 
aeetite of copper, known under tire name of 
distilled verdigris. Iron precipitates cop- 
per from its solution. For tins purpose no- 
thing is necessary but to immerse t .e iron in 
the solution ; the acid seizes on the iron, and 
abandons tiie copper. The copper thus pre- 
cipitated is called copper of cementation. 
M his process is employed for obtaining the 
copper found in water near mines of copper. 
Copper may be alloyed with most of the 
metals. As an alloy of silver it renders it 
more fusible : this mixture is employed as a 
solder for silver plate. Copper, when al- 
loyed with tin, forms bronze, a metal used 
for making bells, cannon, statues, &c. When 
alloyed by cementation with the oxyd of 
zinc, called calamine, it forms brass. "With 
arsenic it forms white tombac. The salts 
formed with copper have a poisonous quality. 
It is employed for making kitchen-utensils, 
but very improperly ; for as these vessels are 
liable to be corroded by the salts and acids 
used in culinary preparations, they often be- 
come dangerous, and may thus make us 
swallow slow poison. Kitchen-utensils of 
tinned iron are far preferable, because iron 
possesses no quality injurious to health. See 
Copper. 
Of iron.— 'So metal is so universally dif- 
fused throughout nature as iron. It is found 
in animals, in vegetables, and in almost ail 
bodies. It is the most useful of all me- 
tals, as well as the most plentiful, otherwise it 
probably would be also the dearest. It is sel- 
dom found native, but combined with a great 
variety of substances, and it is particularly 
distinguished by its inagnetical properties. 
It is the hardest and most elastic of the 
metals. It is very ductile, and possesses the 
property of being welded. It is very dif- 
licult to fuse. 
Exposed to the action of water, iron soon 
rusts or oxydates. It attracts the oxygen and 
carbonic acid, and is changed into a brown 
substance, which is a mixture of oxvd of iron 
and carbonate of iron. Iron-tilings agitated 
in water become oxydated, and assn ihe the 
form of a black powder called martial ethiops. 
\V hen Iron ore is fused in large furnaces, it is 
CHEMISTRY. 
made to flow into a kind of mould formed in 
sand. This first product, which is exceed- 
ingly brittle, and not at all malleable, is called 
cast iron. In this state, by pouring it into 
different kinds of moulds, it is formed 
into stoves, pipes, cannon, and other arti- 
cles. 
Cast or crude iron contains carbon and 
oxygen. The presence of the former appears 
from its coating the utensils employed in its 
fusion with plumbago or black-lead, which 
contains nine-tenths of carbon, and one of 
iron. Crude iron is in three states, white, 
grey, or black, according as it contains a 
larger proportion of carbon, an exact pro- 
portion of carbon and oxygen, or a larger 
proportion of oxygen. To render the iron 
malleable, it must be freed from the carbon 
and oxygen which it contains. For this pur- 
pose it is fused ; and kept in that state for some 
time, stirring and kneading it ail the while; 
by this the carbon and oxygen unite, and are 
expelled in the form of carbonic acid gas. It 
is then subjected to the action of large ham- 
mers, or to the pressure of rollers, by which 
the remaining oxyd of iron and other impu- 
rities are forced out. .The iron is now no 
longer crystallized or granular in its texture ; 
it is lib rous, and ductile, and is in a purer 
state, though far from being absolutely pure. 
It is capable of being welded and worked 
by hammers into any form. It is now called 
forged or wrought iron. 
There are several varieties of iron in this 
state, arising from the intermixture of 
other substances. There is one kind of 
forged iron, which when cold is ductile, but 
when heated is extremely brittle. It is also fu- 
sible. This is termed hot-short-iron. Cold 
short-iron possesses precisely the opposite 
properties, being highly ductile while hot, 
but when cold extremely brittle. The causes 
of these peculiarities have not been perfectly 
explained. Iron is capable of being reduced 
to a third state, which is that of steel. It is 
converted into steel by exposing it to heat in 
contact with carbonaceous substances, which 
unite themselves with it. Thus we have 
three states in which iron may exist, viz. 
cast iron, forged iron, and steel. 
Cast iron contains too great a quantity of 
carbonaceous substance: it may be called 
steel too much steel ifi ed ; it is therefore ex- 
ceedingly brittle, and not at all malleable. 
Forged iron is iron purified from all foreign 
substances. 
Steel is formed by bedding in charcoal, in 
a close furnace,, alternate layers of malleable- 
iron and charcoal, and exposing them to a 
strong lire for six or eight days. This ..pro- 
cess is called cementation. During this 
operation, the iron combines with a quan- 
tity of carbon, and is converted into blistered 
steel. This is either rendered more perfect 
and malleable by subjecting it to the opera- 
tion of the hammer; or is fused, and cast 
into small bars, forming cast steel. Those 
kinds of cast iron which contain but little oxy- 
gen, may be converted into a sort of steel by 
a similar process. In this process, the iron 
gains an increase of weight by the carbon it 
has acquired. 
Steel holds a middle rank between cast and 
forged, or malleable iron. It is composed 
of very small grains, and when hot, possesses 
a considerable degree of malleability. .It is 
specifically heavier than forged iron. It is 
4 
denser than forged iron, but it is not harder 
To communicate to it the necessary hard- 
ness, it must be tempered; that is, alter 
being exposed to a greater or less degree 
ot heat, according to the required degree of 
hardness, it must be suddenly cooled by im- 
mersion in cold water. Tempering renders 
it harder, more elastic, and more brittle. It 
may be made so hard as to scratch glass. 
Steel, thus hardened, may have its softness 
and ductility restored by again heating/ and 
suffering it to cooi slowly. A polished bit 
of steel, when heated with access of air, ac- 
quires very beautiful colours. It lirst be- 
comes of a pale yellow, then of a deeper yel- 
low, next reddish', then deep blue, and at 
last bright- blue. At this period it becomes 3 
red-hot, and the colours disappear ; at the 
same time that the metallic scales, or the ; 
black imperfect oxyd of iron which is formed, 
hicrust its surface. All these different 
shades of colour indicate the different tem- 
pers the steel has acquired by the increase i 
of heat. Artists have availed" themselves of 
this property, to give to surgical and other 
sharp instruments those degrees of temper, 
which their various uses require. Tem- 
pered steel is more elastic, and harder, than 
iron. 
W'ootz, a metal brought from the East In- s 
dies, was examined by Dr. Pearson, who disco- 
vered that it was iron united to carbon, and also 3 
to. oxygen. Iron combines with sulphur and 
phosphorus, forming sulphuret and phosphu- 3 
ret of iron. It combines also with most of 
the metals; but it was supposed till lalelv, 
that it could not be amalgamated with nier-j 
cury. Mr. Arthur Aikm has, however, con- j 
trived a method of "effecting this. Where 
iron is united to oxygen in the proportion of 
73 parts of iron to 27 of oxygen, it forms the 
black or green oxyd of iron, which may be j 
obtained by bringing a bar of iron to a’ red 
heat, and subjecting it to the hammer ; the 
scales which fly off, are the black oxyd of 
iron. This oxyd is attracted by the magnet, 
and if exposed to a white heat in a crucible, 
will absorb 21 parts more of oxygen ; anrl 
is then converted into the red or brown ox- 
yde of iron, and will not be affected by the 
magnet. 
Iron does not combine with oxygen, in] 
more than these two proportions, iron is 
acted upon by all the acids. The nitric acid is 
rapidly decomposed by iron, A portion of the 
oxygen ofthe'acid oxydates the iron, which then 
dissolves, and the remainder of the acid passes I 
off in nitrous gas. Sulphuric acid diluted with 
water being poured on iron, a considerable! 
effervescence takes place, in consequence of 
the disengagement of the hydrogen gas of the 1 
water; its oxygen effecting the oxydation of 
the metal, while the acid dissolves the metal 
without being decomposed. This solution 
yields by evaporation the sulphate of iron. 
Common copperas is this salt in an impure 
state. See Iron. 
Of lead . — This metal is scarcely ever found' 
in the native state. It is chiefly mineralized 
by sulphur, and is then called galena. The' 
pure metal is of a greenish colour. When 
cut it is bright, but soon tarnishes in the air. 
It may be easily cut with a knife, and it soils; 
the lingers when rubbed. It has little or no I 
elasticity. It fuses at 340 degrees Fahren- 
heit. When exposed to heat with access of 
air it fuses, and is oxydated at the surface.] 
