The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1843-10-17 00:00:00

LIVERL 'L POLYTECHNIC SOCIETY

This society held its monthly meeting on Tuesday last,
the 10th instant, at the Royal lositution, the paper for
the evening being by Mr. Spencer. on some new voltaic
arrangements, with itnprovemen's in the art of working
in most of the metals by the sane agency.
We find it impossible to give more than a very brief
abstract of the interesting—we may say important—mat-
t-rs connected in this gentleman's communication, it con-
sisting of a further improvement of the principle of his
former discovery of electrotype, with its practical applica-
tion to purposes of art, together with an account of some
most curious experiments in illustration of the principle
he has now so. successfully applied, and showing the ex-
traordinary power of electrical transference.
Mr. Spencer commenced by stating that the gem of the
principle he was now about to lay before the society—as
applied to voltaic electricity be had already laid before
this body at their first meeting, and many months before,
the paper containing the details of his discovery of elec-
trotype, notice of it having been given as early as the close
of 1838. Although the experiment he alluded to was pub-
lished at the time, and subsequently in a work of his own,
it had attracted no attention, except perhaps as possessing
an abstract philosophical interest.
It was, however, susceptible of most, important results.
Before proceeding further with this branch of the subject,
he took brief notice of the present state of the process of
applying voltaic electricity to the metallurgic arts since
his discovery of its applicability. He also referred to the
dates of his former communications to the society, to show
that the principle and form of his. apparatus at present
employed was precisely the same that he had first brought
under public notice at several meetings of that society !n
1839. Two forms of apparatus were exhibited, being those
referred to as already shown to the members. He then
took notice of several patents that have been obtained for
applications of his principles to several brandies of art;
and although it might appear, in consequence, that much
improvement had taken plice, yet his patents were n errly
for applications of the invention to any branch of business
the party might be engaged in, without laying claim to
anything more—many specifications being literally copied
as respects the progress, from the pamphlet of Mr.
Spencer. which. was published by fhe society in 1839. Se-
veral voltaic combinations were then referred to as having
a connexion with the deposition of metals—one of which
was exhibited in action, it being an invention of his own,
and consisting of a lead surface, made rough by mechanical
means, in order to obtain a numerous series of points. It
is afterwards made to receive two separate coatings of
platinum. The first as solid platinum ; the second being
the same metal in the state of powder—each of which pro-
cesses are effected by electrical agency.
The experiment alluded to at the beginning of the paper
was now brought under notice. It consisted of a piece of
unconnected copper placed in a wall of moist clay, which,
as a division separates two fluids from each other, the
poles of a galvanic fluid being led into each of them. After
the galvanic current thus generated had ben kept in action
for a number of weeks. it was found that the piece of cop-
per had lost con.iderably at one end, while it had gained
an equal amount at the other—yet it had no direct com-
munication with the battery, being merely placed in the
line or wake of the current. It was then shown that in-
duced electricity might be made to play an important part
in the transference of native metals in mineral veins,
although the primary current might be generated at any
imaginable distance. TH.: principle he had now applied
to the manufacture of all kinds of metallic plates, or other
surfaces, but more especially those required for photo-

graphy—a number of splendid specimens of which were
exhibiting, most exquisitely polished, yet jus: in the state
they are in when removed from the galvanic trough they

_ .
ing the result of the galvanic process without th. applica-
tion of labour of any sort. It was stated that plates of this
description were far better fitted—frlm their chemical
purity and equal texture of metal—for photographic pur-
poses, than those constructed by mechanical methods.
A galvanic apparatus, with a plate in the act of form-
ing. was shewn—the apparatus for the construction of
one. fifty, or five hundred, being of equal simplicity. We
shall endeavour to render this as clear as possible without
the aid of a drawing. In all galvanic arrangements
hitherto described, it is necessary to have all the metals

each-other, which is effected by soldering wires, or fasten-
ing slips of metal to them by screws, they must be so done
to etery plate or surface present, whether positive or ne-
gative—furtherniore, both sides of the plates are alike
acted on. To prevent this latter action various expedients
have been resorted to; as for nearly all electrotype ar-
rangements, this is an evil to be avoided, if possible.
Varnishes are used for the purpose of protecting those
parts that are not required to be acted on. In most cases,
however, they are ineff,ctual, as the fluids the plates are
immersed in, frequently dissolve them. It is this com-
plicated system of wires and screws that present such a
formidable appearance to the uninitiated, as it also gives
rise to many failures in practice. By the principle Mr.
Spencer now brings into action, nearly the whole of these
complicated arrangements are avoided, and not only so,
but the metallic deposit is of a far superior texture and
equality of thickness throughout, together with much
of time_ Inhnnr_ snit pytnpnce_ thpro hpincr nn

14):: le waste of material from_ the very nature of the
principle employed. In this arrangement Mr. Spencer,
for the first time, calls into practical operation the hitherto

abstrac

principle of electrical induction. To gives com-
parative idea of his method, suppose we are required to
form a copper plate by the (now common) electrotype
process. wr.. should require a pair of plates, contained in
a vessel, forming our battery. The plate we intend to use
as a mould must be fastened to the zinc plate by a wire,
and then placed in another vessel containing the solution

of the meiai we are desirous of depositing. Anothe plate
of metal, in like manner, has now to he fastened to the
other plate of the battery, and also placed in the vessel
containing the metallic salt in solution. Thus to produce

one plate is required a pairof battery plates, in one vessel,
while another pair must he in an adjoining vessel, to-
gether with four soldered joints or bending screws, and
the back of the plateshave to be burnished, and for every

plate required he required an equal amount of apparatus.
By the method now proposed, however,. the arrange.
ment just described will do for any number of such
plates, no further quantity of wires, solderings, vessels,
or solutions being needful. The trough to be of course

longer will admit the greater number. The plates to be
deposited on are hereby made to stand on end in the fluid,
seriatim, each having a piece of the metal required to be
deposited leaning against it, should there he fifty such
they will be alike acted on. That action which is techni-
cally termed polar, or rasher polariseation takes place—
that is one side of each interposed plate becomes positive,
while the other is negative, and the metal from the posi.
tive side is transferred to the negative side of the next,
and so on, through any number. It was shown this prin-
ciple of action was susceptible of many curious modifi-
cations; among others, that it was capable of keening a
circular body revolving in a fluid for any h ngth of time,
the action of which might be registered like a clock. It
was shown also that a number of such might be kept in
motion, while inductive actions capable of retarding or
accelerating might be obtained at pleasure. In con-
nection with this subject one most remarkable experi-
ment was described, which we regret we cannot give in
full, as the results were most extraordinary. During six
months it was kept in constant action, and the results
noted at intervals. A narrow but long plate glass trough
was divided into four cells, by three porous earthenware
divisions, each of which were 24 inches apart, and had a
small aperture capable of admitting a half sovereign.
The poles of a powerful voltaic pair were placed at each
end of the trough, the positive pole being silver, the
negative platinum. In the first aperture, and next to the
silver pole, a piece of gold was inserted ; into:the next a
piece of silver, and in like manner into the third, was in-
serted a piece of zinc. The whole trough being filled up
with a solution of cyanuret of potassium, and made air-
tight to prevent evaporation, voltaic action was allowed
to go on. The first action that took place was the forma-
tion of a cyanuret of silver and potassium in cell 1,
while in cell 2 was formed a cyanuret of gold and potas-
sium ; in cells 3 and 4, sitnilar salts of silver and zinc
were found. The action being now suffered to proceed
for a few weeks longer and then examined, it was found
that the gold had taken up its position in the next aper-
ture that had been previously occupied by the silver,
while the silver had in like manner replaced the zinc,
which last metal was found deposited on the negative
pole, the aperture formerly occupied by the gold being
now occupied by a disc of silver. We have not room to
describe all the changes that took place during the opera-
tion of this interesting experiment, however the disk of
gold passed through the whole of the apertures in the
solid state, while it was replaced in each aperture it had
left by a piece of silver. These and the other experi-
ments were explained by diagrams and apparatus. Mr.
Spencer next proceeded to explain how by the electro-
type process we have it in our power to diminish any work
of art in metal. This was shown by the fact, that copper
may be deposited either brittle or otherwise, at the plea-
mire of the operator. The brittle copper may then be
annealed. and rendered as tough as rolled copper ; but the
process of annealing always diminished the bulk, while it
increased the specific gravity of the metal. Mr. Spencer
illustrated this fact by taking a piece of brittle copper,
which very readily crumbled under his fingers, and then
by holding it in the flame of a spirit lamp for a very short
time, it was shown to have acquired so much toughness
as to be capable of being bent to a right angle repeatedly,
without breaking. A brittle mould being obtained of the
object required to be diminished, was to be annealed, and
a brittle cast afterwards being taken by it, which in like
manner was to undergo diminution by the same pro.

proceeding in this mai