The solutions generally employed as electrolytes from which silver and
gold are respectively separated, are those of the argento-cyanide and the
auro-cyanide of potassium. These compounds are what chemists call double
salts; for instance, cyanide of potassium is simply a compound of
potassium and cyanogen; but argento-cyanide of potassium is cyanide of
silver united with cyanide of potassium. When a solution of this double
salt is electrolysed silver appears at one electrode and cyanogen at the
other, while a proportionate amount of the simple cyanide of potassium is
formed in the solution. But if the positive electrode is of silver, the
cyanogen combines with it, and forms cyanide of silver, which unites with
the liberated cyanide of potassium, and so keeps up the strength of the
solution.
As in the deposition of copper, the apparatus used for plating or gilding
may be the single cell or the decomposition cell and battery. The
necessity of economising solutions of silver and gold has, however, led to
certain modifications in the apparatus. The single-cell arrangement
consists, as before (see _above_), of an outer vessel of glass or
earthenware, containing a cell of porous biscuit ware; but the object to
be silvered or gilded is placed, with the cyanide solution in the latter,
while the zinc is placed in the outer vessel, with the dilute sulphuric
acid.[273] The zinc is usually employed in the form of a cylinder,
completely surrounding the porous cell. In the battery arrangement the
decomposition cell may be of porcelain or glass; the silver or gold
employed to keep up the strength of the solution may be in plates, wires,
or ingots. For plating small objects, a single cell of a Daniell's battery
will afford ample decomposing power; gilding may be better accomplished by
using three such cells. The battery arrangement is much more convenient,
effective, and economical than the single-cell arrangement.
[Footnote 273: The strength of the acid water acting upon the zinc must be
regulated according to the work to be done. If the action between the acid
and the zinc be too energetic, the electricity developed will be more than
sufficient to release pure metal, and hydrogen will be evolved, which will
interfere with the deposition.]
On a large scale, electro-plating is carried out in oblong vats,
occasionally holding from 200 to 250 gallons of solution. Silver plates
connected with a powerful voltaic or magneto-electric battery, are placed
at intervals in the vats; they form the positive electrodes, and
correspond in extent of surface with the articles to be coated, and face
them on both sides. The articles (tea-pots, cruet-frames, forks, spoons,
&c.) act as the negative electrodes, and are suspended by copper wires
from brass rods laid lengthways over the vats, and connected with the
battery. The articles plated are usually formed of nickel silver or German
silver, which is chosen on account of its silvery whiteness, a quality of
great importance when portions of the coating of noble metal have been
worn away by use.
To prepare the articles for plating, they are first boiled in a solution
of potassa, to free them from grease; they are then quickly dipped in red
nitrous acid, to remove any oxide that may have formed on the surface, and
after this well washed in water, to remove every trace of acid. They are
then suspended from copper wires, and dipped into a solution of mercury in
cyanide of potassium, or some other mercurial solution, and afterwards
washed in water, as before. The amalgamation of the surface effected by
the last operation promotes the adhesion of the film of silver. The
articles having been weighed, are now immersed in the silvering solution,
and left until a sufficient amount of silver has been deposited on them.
Their condition at any time may be ascertained by weighing a test-object
removed from the solution. In some electro-plating establishments the
silvering solution is kept constantly stirred by simple mechanical
arrangements; in others, continual motion is given to the suspended
articles. On being removed from the vats the plated articles are well
brushed with brushes of fine brass wire attached to a lathe, and cleaned
with fine Calais sand; they are afterwards polished on revolving brushes
with rottenstone, then by hand with soft leather and rouge, and, lastly,
with the naked female hand. A lasting polish is given to some articles by
burnishing with a burnisher formed of highly polished hardened steel,
bloodstone, agate, or flint. The process of electro-gilding on the large
scale is nearly the same as that of electro-plating or silvering, but, of
course, plates of gold are suspended in the solution instead of silver
plates.
Various solutions for silvering, plating, and platinising, have been
recommended. We give below those generally employed.
1. Solvent solution. Cyanide of potassium, 2 oz; distilled water or rain
water, 1 pint; dissolve. Other proportions may be employed. Used as a
general solvent for salts of silver, gold, and platinum.
2. Silver solution. Oxide of silver?[274] (not dried), 1 oz.; the solvent
solution (No. 1), 1 pint. Used for the single-cell apparatus, its strength
being maintained as the deposition proceeds by a fresh supply of oxide
from time to time.
[Footnote 274: Precipitated from pure solution of nitrate of silver by
excess of lime water. It should be well washed, and preserved in bottles
with distilled water.]
Cyanide of silver dissolved in solvent solution (No. 1). This is the
solution generally employed for plating with a separate decomposition
cell.
3. Gold solution. Add to a pint of No. 1 oxide of gold, 1/4 oz. Used in
the same manner as the second silver solution.
Cyanide of gold dissolved in solution of cyanide of potassium (No. 1).
Used as last.
4. Platinum solution. The double chloride of platinum and potassium,
dissolved in solution of caustic potassa. Other solutions have been
proposed, but this appears to be decomposed with the greatest ease.
The above sketch of the electrotype art is necessarily very imperfect. For
minute details respecting manipulation, the reader is referred to the
excellent treatises on the subject that have been written; more
particularly to Ernest Spon's valuable work, entitled 'Workshop Receipts.'
=ELEC'TUARY.= _Syn._ ELECTUARUM, L. Electuaries (ELECTUARIA) are formed of
light powders, generally vegetable, mixed up with honey, syrup, or sugar,
to the consistence of a stiff paste. In the present Pharmacop[oe]ia they
are included under the title Confection, but this arrangement is
manifestly improper, as the words are not synonymous. In Conserves and
Confections the addition of the saccharine matter is in much larger
proportion, and is designed to preserve the vegetable matter; in
Electuaries, the syrup is designed merely to communicate the required
form. (Dr Murray.)
The preparation of electuaries is similar to that of confections and
conserves, and the same precautions must be observed to reduce the dry
ingredients to very fine powder before adding them to the syrup or other
substances used to give them form. Care must also be taken to diffuse the
ingredients equally through every portion of the mass, by patient and
laborious stirring. The neglect of this point has often led to
disagreeable consequences, from some portion of the electuary being nearly
inert, while another portion has possessed increased activity. See
CONFECTION, CONSERVE, LINCTUS, &c.
=Electuary of Ac'etate of Potassa.= See CONSERVE.
=Electuary of Al'um.= _Syn._ ELECTUARIUM ALUMINIS, L. _Prep._ 1.
(Ph[oe]bus.) Alum, 1 dr.; extract of logwood, 4 dr.; balsam of Peru, 6
drops; water of sage, q. s. Astringent and antiseptic; in diarrh[oe]a,
sponginess of the gums, &c.
2. (St. Marie.) Alum, 1 dr.; catechu and extract of bark, of each 2 dr.;
conserve of roses, 6 dr.; simple syrup, q. s.--_Dose._ A teaspoonful,
every 4 hours; in chronic diarrh[oe]a, leucorrh[oe]a, hæmorrhages, &c. See
CONFECTION.
=Electuary, An'odyne.= _Syn._ ELECTUARIUM ANODYNUM, L. _Prep._ See
CONFECTION OF OPIUM.
=Electuary, Anti'monial.= _Syn._ ELECTUARIUM ANTIMONII, Fr. _Prep._
Electuary of senna, 1 oz.; guaiacum resin, æthiops mineral, prepared
sulphuret of antimony, each 1/2 oz.; syrup, q. s.--_Dose_, 1 dr. to 2 dr.
twice a day.
=Electuary, Anti-rheumatic.= _Syn._ ELECTUARIUM ANTIRHEUMATICUM; CHELSEA
PENSIONER. _Prep._ Guaiacum resin, 1 dr.; rhubarb, 2 dr.; bitartrate of
potash, 1 oz.; sulphur, 2 oz.; one nutmeg; mix the powders with 1 lb. of
honey. Take two spoonfuls night and morning.
=Electuary, Ar'abic.= _Syn._ ELECTUARIUM SARZÆ COMPOSITUM, E. ARABICUM,
L.; ELECTUAIRE ARABIQUE, Fr. _Prep._ From sarsaparilla, 5 oz.; senna and
China root, of each, 3 oz.; dried walnut peel, 1 oz. (all in fine powder);
honey, q. s.--_Dose_, 1 to 4 dr. See TRAITEMENT ARABIQUE.
=Electuary, Aromat'ic.= _Syn._ ELECTUARIUM AROMATICUM (Ph. E.). This
preparation differs from the aromatic confection of the other British
colleges, in not containing chalk. It is aromatic and stomachic, but not
antacid or absorbent. CONFECTION.
=Electuary, Bath.= _Syn._ ELECTUARIUM ANTI-CACHECTICUM, E. MARTIALE, E.
FERRI COMPOSITUM, L. _Prep._ From blacksmiths' clinkers, reduced to an
impalpable powder, and made into an electuary with honey or treacle, q.
s.; afterwards adding powdered ginger and carbonate of magnesia, of each,
1 oz., to every lb. of the mixture.--_Dose._ A teaspoonful night and
morning every day, for 3 or 4 days, and again, after an equal interval, as
long as thought necessary; as a chalybeate tonic, and in worms.
=Electuary of Bitar'trate of Potas'sa.= _Syn._ ELECTUARIUM POTASSÆ
TARTRATIS, L. _Prep._ (Monro.) Cream of Tartar, 1 oz,; powdered ginger and
conserve of roses, of each 1 dr.; syrup of orange peel, q. s.--_Dose_, 1
to 3 dr.; as a hydragogue purge. It is also a useful laxative in common
cases. See CONFECTION OF CREAM OF TARTAR.
=Electuary, Black.= _Syn._ TROUSSEAU'S ELECTUARY, TROUSSEAU'S BLACK TONIC;
ELECTUARIUM NIGRUM, E. FERRI TANNATIS, L. _Prep._ From sesquichloride of
iron, 4 dr.; tannin, 1 dr.; confection of roses, 2 oz.; syrup of orange
peel, 1 oz. Tonic and astringent.--_Dose_, 5 to 30 gr.
=Electuary of Black Pep'per.= See CONFECTION OF PEPPER.
=Electuary of Burnt Sponge.= _Syn._ ELECTUARIUM SPONGIÆ USTÆ, L. _Prep._
(Hulse.) Burnt sponge, 10 gr.; rhubarb, 4 gr.; conserve of roses, q. s.
For a _dose_, to be taken night and morning; in scrofula, glandular
swellings, &c. See CONFECTION OF SPONGE.
=Electuary of Cas'sia.= _Syn._ ELECTUARIUM CASSIÆ (Ph. D. 1826.), E. C.
FISTULÆ (Ph. E.), L. _Prep._ (Ph. D. 1826.) Fresh cassia pulp and syrup of
orange, of each, 1/2 lb.; manna, 2 oz.; tamarind pulp, 1 oz.; mix, and
evaporate to a proper consistence.--_Dose_, 2 dr. to 1 oz.; as a gentle
laxative for children, or as a vehicle for other cathartics. That of the
shops is commonly made with equal parts of tamarind and cassia pulps,
mixed with 1/8th of manna, and flavoured with a few drops of tincture of
orange peel, without any evaporation. See CONFECTION.
=Electuary of Cat'echu.= _Syn._ ELECTUARIUM CATECHU, CONFECTIO C., C.
JAPONICA, L. _Prep._ (Ph. E.) Powdered catechu and kino, of each, 4 oz.;
cinnamon and nutmegs, of each, 1 oz.; opium (dissolved in a little
sherry), 1-1/2 dr.; syrup of red roses (evaporated to the consistence of
honey), 1-1/2 pint. See CONFECTION, and _below_.
=Electuary of Cat'echu (Compound).= _Syn._ ELECTUARIUM CATECHU COMPOSITUM
(Ph. D.). See CONFECTIONS. Both the above are astringent, aromatic, and
anodyne.--_Dose_, 15 gr. to 1 dr., or more; in diarrh[oe]a, dysentery, &c.
=Electuary, Cathar'tic.= _Syn._ ELECTUARIUM CATHARTICUM, L. _Prep._ 1.
Confection of senna, 1-1/2 oz.; flowers of sulphur, 1/2 oz.; syrup of
roses or of orange peel, q. s.--_Dose._ A teaspoonful, 3 or 4 times a day,
in piles; or, 2 to 3 teaspoonfuls, as a gentle laxative for females, and
in skin diseases, gonorrh[oe]a, &c. A mild and excellent medicine. It may
be safely given in larger doses.
2. (Brera.) Aloes, 8 gr.; cream of tartar, 2 dr.; honey, q. s. For a dose.
In amenorrh[oe]a, attributed to abdominal engorgement.
=Electuary, Cephal'ic.= _Syn._ ELECTUARIUM CEPHALICUM, E. VALERIANÆ
COMPOSITUM, L. _Prep._ (Hosp. F.) Valerian root and mistletoe of the oak,
of each 1 oz.; honey, 1-1/2 oz.; tincture of henbane, q. s. to make an
electuary. In nervous and rheumatic headache, &c.; assisted by an
aperient.
=Electuary of Char'coal.= _Syn._ ELECTUARIUM CARBONIS, E. CARBONII,
CONFECTIO C., L. _Prep._ 1. (Hosp. F.) Confection of senna, 2 oz.; fresh
burnt charcoal, 1/2 oz.; carbonate of soda, 1/4 oz.; syrup of orange peel,
q. s.
2. (Radius.) Electuary of senna, 2 oz.; powdered charcoal and carbonate of
soda, of each, 1 dr. Both the above are given in obstinate
constipation.--_Dose_, 1 to 3 teaspoonfuls twice a day. See ELECTUARY FOR
THE TEETH.
=Electuary for Chol'era.= _Syn._ ELECTUARIUM ANTI-CHOLERICUM, L. The
preparations that come under this name are numerous, including aromatic
confection, and several like absorbent or astringent preparations. This
name has been given to the American remedy for cholera, noticed at page
=Electuary of Cincho'na Bark.= _Syn._ ELECTUARY OF BARK; ELECTUARIUM
CINCHONÆ, L. _Prep._ 1. From yellow bark and simple syrup, of each 1 oz.;
conserve of red roses and confection of orange peel, of each 1/2 oz. Tonic
and febrifuge.--_Dose_, 1 to 4 dr.; in debility, agues, &c.
2. (Radius.) Peruvian bark, 1 oz.; syrup of orange peel, q. s. As the
last.--_Dose_, a teaspoonful or more, 3 or 4 times daily. (See _below_.)
=Electuary of Cinchona (Compound).= _Syn._ ELECTUARIUM CINCHONÆ
COMPOSITUM, L. _Prep._ 1. (ACIDULATED,--Copland.) Yellow bark, 1 oz.;
confection of roses, 1/2 oz.; diluted sulphuric acid, 1 dr.; syrup of
ginger, 1-1/2 oz.
2. (ASTRINGENT,--Saunders.) Powdered Peruvian bark, orange peel, and
conserves of roses and hips, of each 6 dr.; crabs' eyes (or prepared
chalk), 2 dr.; syrup of catechu, q. s.--_Dose._ A teaspoonful, 2 or 3
times daily; in chronic diarrh[oe]a, &c.
3. (WITH CATECHU,--Pierquin.) Peruvian bark, 1 oz.; catechu and balsam of
tolu, of each 1 dr.; syrup of comfrey (_Symphytum officinale_,--Linn.), q.
s.--_Dose._ As the last; in spitting of blood, hæmorrhages, &c.
4. (WITH CLOVES,--Dewees.) Peruvian bark, 2 oz.; cloves, 1 dr. (better, 4
dr.); simple syrup, q. s. A piece the size of a walnut, every hour or two,
during the intermission of an ague.
5. (WITH IRON,--Cadet.) Peruvian bark, 6 dr.; oxide of iron and confection
of opium, of each 2 dr.; syrup of cinnamon, q. s.--_Dose._ A teaspoonful,
or more, twice a day; in dropsy of the belly, after the evacuation of the
fluid, and as a tonic in debility, accompanied by nervous excitement, &c.,
in the absence of fever.
6. (Quarin's.) Red bark, 1 oz.; ammoniated iron, 1 dr.; made into an
electuary with equal parts of oxymel of squills and syrup of the 'five
roots' (diuretic). Tonic, febrifuge, and pectoral.
7. (WITH SAL-AMMONIAC,--P. Cod.) Gray bark, 2-1/4 oz.; hydrochlorate of
ammonia, 1 dr.; honey and syrup of wormwood, of each 2 oz. In
intermittents occurring in scrofulous subjects.
8. (WITH SODA,--P. Cod.) Powdered cinchona, 1 oz.; carbonate of
soda, 2 dr.; thin mucilage, q. s. to mix. Tonic, febrifuge, and
stomachic.--_Dose_, 2 dr., 2 or 3 times a day; in agues, complicated with
acidity and dyspepsia.
9. (WITH SULPHUR,--Cadet.) Peruvian bark, 1 dr.; sulphur, crabs' eyes
(chalk), and spermaceti, of each 2 dr.; extract of opium, 4 dr.; conserve
of roses, 4 dr.; syrup of milfoil, q. s. Highly praised in debility from
phthisis.--_Dose._ A teaspoonful, 2 or 3 times a day, assisted with the
liberal use of raw or lightly boiled eggs and cod-liver oil.
10. (WITH TIN,--Cadet.) Peruvian bark 1 oz.; tin filings and valerian
root, of each 1/2 oz.; syrup of saffron, q. s. In epilepsy, worms,
&c.--_Dose._ A teaspoonful, morning and evening. See CONFECTION OF BARK.
=Electuary of Copai'ba.= _Syn._ ELECTUARIUM COPAIBÆ, L. _Prep._ 1. Copaiba
and powdered cubebs, equal parts; conserves of roses and orange peel, of
each (in equal quantities), q. s.
2. (Caspar.) Blanched almonds, 6 dr.; powdered marsh-mallow root, 1 dr.;
catechu, 1/2 dr.; balsam of copaiba, 3 dr.
3. (Ricord.) Confection of almonds, 1 oz.; copaiba, 1/2 oz.; hard extract
of rhatany, 3 dr.; syrup of orange peel, q. s. All the above are excellent
in gonorrh[oe]a, gleets, &c. The last two agree better with the stomach
than most other like preparations.--_Dose_, 1 teaspoonful, or more
(rapidly increased to 2 or 3 dr.), 3 or 4 times daily. See CONFECTION.
=Electuary of Cow'hage.= _Syn._ ELECTUARIUM DOLICHOS, E. MUCUNÆ, L.
_Prep._ 1. Dip the pods of dolichos in treacle, allow them to drain a
moment, and then scrape off the hairs for use.