Daily tobacco leaf-chronicle. (Clarksville, Tenn.) 1890-1895, 1890-06-07
eLecTAePtATINe.
Description of the Interesting Process
and Its Modern Improvements.

PROCESS
and Its Modern improvements.
z Electroplating was formerly done by
covering the metal to be gilt with gold leaf
by hand, or with al anslgam of gold and
mercury, and then yolatilizing the latter
metal, and the same process was employed
in silvering. In 1893 Bruguatelli succeeded
in gliding the baser metals by means of a
galvanic current. but the first to make the
process a success was the chemist De La
Riva, and it has since been greatly inn
proved by later Investigators.
The process depends upon the peculiar
power which the voltaie current possesses
of separating certain compound bodies into
their constituent parts.
For instance, if a current from voltaic
battery is passed by means of platinum
electrodes through water to which sui
phrric acid has been added, this chemical
separation, which is called electrolysis
win take place, the water being resolved
into its constituent gases. oxygen and
hydrogen.
Now, if some sulphate of copper is
thrown into the liquid electrolysis will still
go on with double result-the water will
be separated into its elements, and the by
drogen, by it's stronger affinity, will form
a new compound with the sulphur in the
sulphate, setting the copper free. and the
liberated copper, being electro positive in
character, will be deposited on the plat
mum electrode, which is negative.
On this general principle the process of
electroplating or electrotyping depends,
and it's art consists in applying the metals
thus released from their solutions to artis-
tic and useful purposes. The solutions
generally employed lis electrotypes from
which to separate gold and silver respect
lively are those of the argento cyanide and
the auro cyanide of potassium.
These compounds are what are known &c
chemists as double salts; that u.s. while cy
anide of potassium is simply compound
of potassium and cyanogcn, argento eva.
hide of potassium is cyanide of silver com
bined with cyanide of potassium When Il
solution of this double salt Is subjected t.
the action of electricity, silver appears al
one electrode and cyanogen ct the other
while the cyanide of potassium. from
which the ntner salt had been thus separai
ed, reappcars in the solution.
1t is the negative electrode which takes
the silver, and if, therefore, the positive
electrodc is made of silvsr, the liberated
cyanogen combines with it, forming cyan,
ide of silver, which, by uniting with the
liberated cyaLide Of potassium, keeps the
strength of the solution to the proper de
gree The apparatus used is an outer YES.
sci of glass or earthenware, in which is u
smaller vessel of biscuit ware or other por
Gus material.
In the smaller vessel is placed the sui
phuric acid, with plate of amalgaAate
zinc. The cyanide solution is in tie QUITE,
vessel and In it is suspended the object C
be silvered or gildcd, which is connected by
IA wire with the zinc in the cell to eonver
the galvanic current. Hhe strength Of this
current must be reyllItod; if the aril is
very powerful the electricity developed will
be more than sufficient to release the metal
and hydrogen will be evolved, which will
interfere with the plating process. To carry
on electroplating on large scale obonr
watts are used, which may hold POO gallons
of solution.
Silver plates connected with a powerful
voltaic battery are placed ut intervals H.
the watts; they form the positive electrodes
and correspond in extent of surface with
the articles to be coated, and face them on
both sides.
These articles-knives, forks, spoons,
cruet frames, teapots, urns, etc. -sat as
the negative electrodes, are suspended by
copper wires from brass rods laid lehgth
wise over the watts and connected with the
battery.
The articles are prepared for plating by
being first boiled instrong lye. to free them
from all grease; they are then quickly dip
ped in muriGtic acid to remove any oxide
that may have formed on the surface, and
after this are well washed in water TO re
move every trace Of the acid
They are then dipped into solution of
mercury, and then washed in water again
The effect of the latter operation in to make
the film of silver adhere more readily The
articles are then weighed and suspended in
the solution, and are left there until suf
ficient amount of silver has bean deposited
upon them.
This amount is tested by weight. If the
additional weight is not gained in the ex
pccted time tn. article is put in the solu-
ton again. J
When finally taken out the articles are
brushed with brushes Of fine wire and
cleanscd with fine sand; they are then pol
ished on revolving brushes with rotten
Stone, then with channels leather and rouge
and lastly with the naked hand
The process of electrogilding is essential
Iy the same as that given above for silver
ing, substituting gold for silver Golden
Days