The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1836-12-30 00:00:00

than £lOO,OOO. Of the advances to customers, a great portion are
believed to be on the security of its own shares, the rtcovery of
which is not to be calm:hit-A on. it is admitted in this account
that the discrepancy struck the directors whim) existed between
the statement given and the evidence of the London agent be-
fore the joint-stock bank committee, vet with these and other
causes of suspicion, on mere verbal information, they consented
to advance had* a million, and have in consequence become en-
tangled farther with the concern to the extent of es much more
at least. The directors, therefore, now standin.this dilemma
with the' sound end reflecting men of business in the city—that
they were either imprudent beyond ail Conception in the trans-
action, or that, they had motives for this transaction which are
nut yet fully apparent. The plea of generosity and a desire to
protect the public wilt not avail them to the 'extent which they
imagine; and they very well know, that if the winding-up, as it
is not unlikely to do, should leave them with a very' large defi-
cit, the assigning of such a motive would bc'very coldly received
at the next court. of proprietors. Any man who is aware of the
nature ofpublic bodies will say, that they, never are nor can be
actuated by any such motives. The directors appear them-
selves to he already sensible of the consequences that may attend
'this step; they betray fears that, having established the prece-
dent in assisting this- bank, they will be compelled to go on;
and they declaim loudly, at the same time, against the general
rottenness of the joint-stock bank system. the propping up of
which they now apprehend must fall upon them. In fact, it is
evident that they are now convinced that, being placed between
a choice of evils, they have selected the worse of the two. The
disclosures which will be made of the management of the North-
ern Bank In the comae of the inquiry which has just begun are
Very eagerly looked for. .It.is.now said that the managers, in
the interval between the first and Second application to. the
Bank of England, have sold four of the branches. This of itself
Was an infraCtion of the original contract; that a falling con-
cern should find purchasets is, however, by no means new •in
banking affairs.—Times.

A POPULAR COURSE OF CHEMISTRY, AT THE

MECHANICS' INSTITUTION.

LECTURE XII.

On Saturday evening Hemming delivered the last of his
interesting lectures, at the conclusion of which he was-greeted
with the warmest applause by his numerous audience.
We have- to consider in this lecture the two metals. copper
end lead,' for the production of which 'England is highly and
justly celebrated. 'Copper has been found no where in a state
of greater purity than in Great Britain, in the counties of Corn-
wall and A tiglesea ; vet .200 years ago copper pyrites, from
which the greatest portion of the metal is now obtained, was
throWn away by ,the miners in their search after tin, for the art
of reducing it to metallic copper does not appear to have been
knowo. ind'eed,•copper and iron, as previously stated, are the
most difficult of all the metals to reduce to the metallic state.
It will be remembered that it has been mentioned, that in for-
mer times, before 'the art of reducing iron was known, all
weapons and implements were made of an alloy of impure
copper and tin. More that' '2OO years ago tin was exported to
Rome for the purpose of manufacturing this alloy. Indeed, so
great was the export, that it is supposed that island acquired its
appellation of Britain from this circumstance—" Brach tan,"
meaning the laud of tin. In South America large masses of
copper are found looking like meteoric iron, which are supposed
of meteoric origin. end contain nickel. Indeed, masses of iron
have been found in the ground which lead us to suppose that
they have been deposited there in a fluid state, as the prints of
cattle feet are found plainly marked upon their lower surfaces.
Copper is found in all parts of the world, but no where more
abundant than in Cornwall and Anglesea. It is found in small
quantities in • the Isle of Man, and an island near Guernsey.
Altnest'all the copper ore found in Cornwall is sent to Swausea
to be reduced, fur this 'reason, it will take three tons of coals to
reduce one ton of copper.. It- is therefore more economical tp
export one ten of copper to Swansea, than it would be to import
three tons-of coal to Ceruwall. Different portiers of a . copper
mine are let Out- by the proprietors to certainsitoliyiduals, and
they engage to get the ore at so much per cent. upon the value
of the metallic ore.• This takes place periodically, perhaps
weekly, monthly, or so on, The miner 'then provides his own
men .to procure i:. The first step is to bore the •rock, and then
to ram the hole full of gunpowder. This being done, a small
piece of touch paper is insertsd; prepared by immersing paper
in a solution of saltpetre, and carefully drying it. When one
end of this paper is ignited, the fire slowly traverses to the other
end, hail meeting with the gunpowder, it produces an ex-
plosion. This show - ignition of the touch, mice enables the
miner to escape from the danger before this explosion takes
place. But it Must be acknowledged that this is a vulgar and
unscientific process of blasting, as the .fire sometimes travels
faster than the miner anticipates, and endangers ,his • life. A
better mode is frequently adopted e: a small hollow rope covered
with tar is filled with wet povrder, which burns like a boy's
and as a foot of this will burn in a minute, tne millet is
enabled to escape with certainty. The miner .extracts the ore
loosened by the explosion el the gunpciwder by Means of a
pickaxe, and brings it to the surface of the •earthin baskets or
buckets, which are hoisted up by machinery. The use is then
beaten into smallpieces, after this it is reduced to the state of
coarse powder, as most of . the metalliC ores. This is still
done in some parts, by means of stainpers or by ham-
mers; but in Cornwall they have three pairs of steel or
case-hardened e rollers. revolving in contrary directions, one
pair, placed above the other. The Ore, is iu. the first place
passed
,between the first pair, and in passing through be-
comes crushed and reduced in size ; it then passes between the
second pair of rollers, and is still. further reduced in size; the
third pair of rollers are placed still closer together, so that the
ore in passing between them is reduced to. time state of a coarse
powder. The next 'process is that of washing, to seoarate sili-
emits and earthy matter, some of which ere.eiseful tore certain
extentenreduciog the ore. These siliceous particles areeriepa-
rated orean inclined plane by allowing a stream of water to pass
slowly, over the ore. ,These inipuritiee are much lighter than
the powdered metal, and, therefore, are washed away, while the
;heavier metal remains, and is removed from time to ',time.
§otneliines the process of jigging has been reshrtect to. It coo-
srists in placing the powdered ore in sieves, and shaking it
,in
:them :beneath the surface of the water.• By this means the
heavier particles of metal either pass through the meshes of the
wire or rest upon them whilst the lighter siliCeous matter is
scraped off the surface of the copper ore and removed. This
operation used to be performed by women, who stood up to
their knees in water in seasonable weather, whilst engaged in
it. There is a. much better mode than this ,now adopted in
Cornwall. A large tank is so contrived, that by the action of a
plunger the water alternately rises and falls through large
sieves in the corner. of the tank, by which means the heavier
particles of metal are enabled to gravitate as in the former in-
stance, and the -lighter ones to rise to the surface. The differ-
ent samples of ore are then collected together end assayed. The
miner has one portiori, and Lie owner of the mine another, out
of which the miner pays a certain percentage for the cost•of the
candlee,)the gunpowder, and other mining requisites. The ore
is sent to Swansea to be reduced, and here comes the most diffi-
cult part of the whole, which makes it a wonder that copper was
not reduced to a state of purity in former times. The copper' is
first roasted to deprive it ()fits arsenic and sulphur. This opera-
tion of roasting is commonly performed in a reverberatory fur-
nace, and in most cases the arsenic and sulphur are deposited
upon the surrounding couutry, which it quickly renders infer-
tile. In some places, however, the fumes ofsulphur and arsenic
are condeused in a chamber. The sulphur thus obtained is
sometimes used in the manufacture of sulphuric acid. After
this process of roasting, the process of reduction commences.
It is mixed with large. quantities of coal, and heated intensely
in a reverberatory furnace. It is brought to a state of fusion,
when the silica contained in the ore combines with oxide of
iron and forms silicate of iron. This combines with various
oilier impurities in the ore and floats upon the top of the melted
metal. The upper portion of the furnace is' then tapped, and
the melted slag is run out into moulds, and it forms a very good
inatettal for building, far superior to any stone or brick we are
acquainted with. The metal is then run out into water, where
it is granulated into irregular
_grains.. These are, then taken
out of the tank of water and 'submitted to a similar process of
fusion, from which the slag is again separated. This process is
repeated several times—sometimes eight, until the iron and
silictiere almost entirely separated. • After this, whew the work-
man considers that-it• is sufficiently pure, it is cast into pigs,
which 'ere broken and roasted, and then it is ready to be refined.
Then begins the process of refining the copper; small quanti-
ties of iron• And small quantities of sulphur and of oxygen being
still combined with it. To separate these it is brought into a
state of fusion with charcoal, and kept covered with charcoal.
Atter a time a small sample of it is taken out by a ladle fur
the purpose of enabling the workman to judge if it is suffi-
ciently purified. If this breaks when cold with a silky frac-
ture, and is somewhat soft, it is considered good. If it is
pretty ductile it is fit for the last operation called polling, the
rationale of which we are not to this day able to account for.
This is performed by introducing into the. molten metal a• birch
Pole, and continually stirring it about. This excite. considers
able effervesence, and of course a short time the external
portion of the birch pole becomes coated with charcoal. Whether
the potaesinin is liberated and converted into an alloy with the
metal or not we de not know. The copper. is not tnalleable
without the polling, and if it be pulled too much it again be-
comes brittle, and is again obliged to be heated with charcoal,
and then polled again. Wheu the copper is thus refined it is
cast into moulds or cakes as required. In Anglesea the copper
pyrites centeins se miich sulphur that when ignited in a pow-
tiered • state it has continued burning for six mouths at a
time. In this island a vein richer than any in the world was
fuund,imeasuring 70 feet in thickness, out of which 20,000 tons
of copper have been raised in one-year. There is this advan-
tage attending the chemical coinhination of copper and sulphur
that they will continue burning together for a long time; even
if placed in vacuum or in au atmosphere of carbonic gas,
`which will only admit of the burning of that remarkable. metal,
potaseSurn. Is is said that In AitgleeeaethlS ilperetieu hAsebeetiel
carried tom for six months together: and the copper thereffire his-
been in a much better state fur the subsequent procAses of re-
duction and purification.
When thus reduced, copper is a metal of a brilliant red co-
lour, and the brilliancy of the culour is improved by plunging
it when hot non water. It loses its brilliancy wholly by ex.
posure to the atmosphere in eonsequenne of combining with ox-
ygen and carbonic acid. forming on its surface,a crust of car-
bonate of copper. If we heat the copper to redness in atmos-
pheric air, the surface of it will be covered with pure oxide of
copper; when thus reduced to the metallic state copper is a vert
malleable and ductile metal. It May he reduced to leaves, tle•
l-100,000"ot au inch in thickness. kis a difficult metal to melt,
and also to burn it. .It will melt. at 2,000 degrees, or burn by a
current of oxygen gas. All the salts of copper, if we cen burn
them, •will exhibit a green flame. If for example we take a lit-
Ile of the nitrate of copper, and pour it upon a sponge slipped
in alcohol the flame will appear of a green colour. Indeed. in
the analysis of ores wo may consider thet copper is present when
this peculiar flame is observed, for there are very few of the
metals that will present a similar appearance. We appear to
have two oxides of copper, respecting which there is touch dif-
ficulty. The protoxide may be got by heating copper to redness
and plunging it into cold water, when the scales which will fall
off will be the protoxide. We may also make it by dissolving
It was supposed to
copper in nitric acid, precipitating by an alkali, and heating the
er and two of precipitate to redness. It appears to be combined with one
• equivalent
nonf
icionpnpoefroannedeognuei
vaolfenotxoyigteoni.v
klings, in. boiling
oxy-
gen, but this is mot found• to he a peroxide, but a protoxide.
ful :in attraction for.
There is an oxide differing-from this compound which may be
k
'''')ltiPe"iirotoxiile is valu-
itthad e
withbys
übge:rt beating
(tiltliei
yegos,sxieli
,'powerful
j(
oxygen that it is impossible to,expose it to the atinesphere with-
nut the combines
able because it. forms the base of all the' salts of -eirese.r. The
most valuable of the salts of copper are the sulphate and the
nitrate. .The sulphate is found in very great abundance in
some mines; being caused by the action of the air and water
,utrilluolthtehe"a"i'rPael'oll"'iittee'r. If these pyrites toe exposed to the
the mu Iphur emnbi,,, with the
ox.
yeen.of thei and the water, forming eulphuric acid amid the
celiner with the °Nygr g, ,en forminopper, when,, the sol-
i
phliiie
apt 4 dissolves
the okid,,of copper, at,' limns selpheret
cooper which remains-id kolution.; • Many itt• our (111UVS, especi-
alit' in island
ofo 4.oll,tiettet , o,• Con to ;
ies
sulphatieel (-tippet ieseitekrfeisilUtion. the weter at 0.4 bettem
,of thesmio Pt: bein g deeellyTidirs'ired troll The nee 'sod value
if. this ,seeiniabeappeaes Alteriseefsieen (11.;t:evetpd 4y, ;ate
dent, in the mines of Wicklnw, the- •eator,fistue,wiere
,a,„
formerly pumped sway as valueless. It nappened by accident
that an Irish tabourer left hie Spade in a paddle of water. and
found to his great astowshinent, on his return, that the iron