Part II.
A variety of curious and valuable experiments on gold and silver, shewing the method of testing, refining, separating, allaying and toughening those metals; together with other receipts, for gilding &c.
Previous to entering upon the several detached reon gold and silver, it may be proper to give a brief sketch of metallurgy ; or, in other words, " The art of extracting and purifying of metals, in the great way."
After trial has been made on a small scale (which is called an Assay) that any particular mine is likely to be profitable, the workmen proceed as follows : They dig a perpendicular square pit, large enough to admit ladders, whereby they may descend. Across the mouth of this pit, which is called a shaft, an axis is usually laid, for the pur¬pose of raising buckets loaded with the mineral ; and pumps are also placed, for carrying off the drainage water. If the depth of the mine be so great as to exceed the due proportion of the first square pit, an horizontal drift is formed, at the end of which a new shaft is sunk, and so on alternately till they reach the bottom of the ore-mine. The drifts, which resemble galleries in some measure, are propped up by art, if the stratum through which they pass is of too crumbly a texture to support itself. Regular supplies of fresh air ought at all times to be kept up.
Sometimes it is practicable to open an immediate passage to the plane below ; but if this cannot be effected, a new shaft is sunk at that part of the drift or gallery which is furthest from the former shaft, so that if one of these is higher than the other, the air easily circulates. When, however, they are equally high, a fire is kindled in a fur¬nace over the mouth of one of the shafts, and thus a sup¬ply of air is gained. Again, the pumps which are usually employed to take off the drainage water are sometimes insufficient for the purpose, for a sudden burst of water will in a moment inundate the galleries ; in this case, the workmen, having warning by the peculiar sound of the rock when it is struck, cut the rock to give vent to the water, and retreat behind a door which they have pre-pared, which shuts out the fluid from overtaking them. — Mines are subject to elastic vapours, which are extremely dangerous to the workmen : their effects are prevented by rapid currents of fresh air, or by detonation.
When the mineral is brought out of the mine, it is pounded, washed, roasted, melted and refined. For pounding large knockers are moved some strong mechanical power and after pounded, put on inclined tables, to be washed, that the water may carrv off the gangue, matrix, or immediate bed of the ore. When ores contain sulphur they should be roasted in the open air, otherwise they may be roasted in the furnaces in which they are to be afterwards melted. Some ores will melt by themselves others require flux for fusing them, and
xnust be brought in contact with charcoal. The furnaces which are employed arc of various kinds ; but, sometimes, the same furnace will answer two purposes. Although metals are by these means reduced to a metallic state, yet they are frequently mixed together, of various kinds, and they therefore require some further processes to separate them.
Of gold.
Gold, which has been termed sol, the suit*, and king of metals, is a perfect metal, of a splendid yellow colour, and not liable to alteration. When gold is very pure it loses in water between a nineteenth and a twentieth of its weight. A cubic foot of gold weighs 1326 pounds: its hardness is not very considerable, being in an intermediate state between the hard and soft metals. It is extremely malleable, and spreads readily under the hammer; and by the hand of a skilful artist may be wrought into any shape or form. So wonderful and surprising is its ductility as to nearly exceed belief. From absolute experiments, an ounce of gold may be beaten into a leaf that will cover ten acres of ground ; and an ounce of gold mav be made also to cover, perfectly, a silver wire that is 444 leagues,
or 1332 miles, or 2,344,320 yards, or 7,032,960 feet, or 84,395,520 inches, in length. A single grain of pure gold has been extended over an area that is more than fourteen hundred inches square ; and a wire of the same metal,
only one-tenth of an inch in diameter, has been found so tenacious as to support five hundred pounds weight, with¬out breaking. Long hammering will make it rather brittle,
but heat soon restores its ductility, which is termed neal-ing or annealing. The colour of gold sometimes varies, but this is owing to some mixture or alloy. When it is pure, it is called gold of 24 carats ; and as the number of
earats decrease, so much the more is the alloy (generally of silver or copper) ; thus, one quarter of silver, and one quarter of copper, to one half of gold, incorporated to¬gether, make a gold of 1 2 carats ; and this is specified on the bars or ingots. Gold is unalterable by air or water ; and the dulness which may appear occasionally on its surface is entirely owing to extraneous matters, and not to rust. The action even of fire, long continued, makes no alteration of its substance. When it has acquired a vivid redness, it soon melts ; but it emits no fumes, and suffers no loss of weight whilst in fusion. Kunckel kept gold in a glass-house furnace for a month ; and Mr. Boyle kept it in a similar furnace for a much longer time, without the loss of a single grain. Simple chemical agents are unable to make any impression on gold, but compound bodies, such as aqua regia and liver of sulphur*, dissolve it power¬fully. Gold has a much greater affinity for mercury than any other metallic substance has, and it will therefore de¬compose amalgams of any other metals with mercury. The amalgam of gold with mercury is of a higher and more solid colour in proportion to the greater quantity of gold. This amalgam is liquified by heat, and will crytal- lize on cooling, like most of the compounds of this kind. It is used principally by the workmen in gilding in water¬
gold, termed water-gilders. An alloy of silver with gold produces green-gold, which is used by the jewellers.
As gold is a standard, used by most nations, to repre¬sent the value of the productions of nature and art, it is highly necessary and important to discover its extreme purity, and to be able to detect any fraud which may have been used to encrease its bulk. Chemists are in the pos¬session of a method of testing and this peculiar process termed cupellation which as follows.
These old names are retained, in lieu of nitro-muriatic acid and sulphure of potash of the new nomenclature, because they are sold by these names in the shops, and are so called by the workmen in gold and silver. Ed.
Method
GOLD AND SILVER WORKS.
Method of testing Gold by Cupellalion : used also in testing of Silver.
The process of cupellation is the art of destroying, vi¬trifying and scorifying all the imperfect metals which are de¬structible, and which are extraneous to pure gold and silver.
We see then, that the examination, or assay, of the purity of gold or silver, separately considered (for when they are mixed, and purified from their several ores, on a large scale, it is termed refining) is no other than ascertaining the difference of weight between the residue of the metal, after the operation, and its primitive state. A quantity of lead, proportionate to the supposed quantity of alloy, is mixed with either of the purer metals. This mixture is put into flat porous vessels, called cupels, made of the powder of calcined bones kneaded with water ; or the latter composition is crammed into an iron ringle, see plate iv. fig. 1 . After this, it is exposed, for a length of time, to the strongest heat of a reverberating furnace, till the imperfect metal, lead, is totally scorified, or, till the gold, or silver, which ever is the subject of the operation, assume a dazzling brightness. At this time it will be found, that the bone ashes have absorbed the impurities, and the pure metal forms a bright metallic button in the centre of the cupel. In determining the quantity of im¬purity the purer metal contained, it is considered as con¬sisting of twelve parts, which are called penny -weights, each of which are divided into twenty-four grains. If the mass under consideration has lost in the cupel only the twelfth-part of its weight, it is said to be of eleven penny¬weights ; if it has lost only a twenty-fourth part of its weight, it is said to be of eleven penny-weights and twelve grains fine.
Of separating Gold from Silver.
Although gold and silver may be perfectly separated from the more imperfect metals by the afore-mentioned process, yet they cannot be separated from each other by the same means, because they equally withstand the heat of the furnace : other methods, therefore, are em¬ployed, which are termed parting, viz. bv solution, by ce¬mentation, and in the dry -jtaij \ oi which, separately,
Parting of Gold from Sliver, by Solution.
Parting by solution is usually termed parting by aqua fortis. The aqua fortis, which is used for this pur¬pose, must be extremely pure, and free from any ad¬mixture of other acids, otherwise the other acids will
keep a part of the silver dissolved within themselves, forming other compounds, which remaining mingled with the gold, will keep some of the silver unpurified by the
process. Another material circumstance, beside the pu¬rity of the aqua fortis, is, a due knowledge of the pro¬portions of the two metals to each other ; for if the
gold exceed the silver in quantity, the latter will be co¬vered by the former, and thus be guarded from the ac¬tion of the acid; which, it should be observed, is not a solvent of gold. When assayers, therefore, want to know the proportion of gold to silver in the mass, they rub the mass upon a touch-stone., so as to leave a mark upon
it; they then make similar marks with their proof needles (which are needles composed of gold and silver allayed
together in graduated proportions), and by comparing the colour of the several marks, they discover the probable scale of admixture. Having ascertained this point, they add more silver, if necessary, and the mixed metal is
cither rolled up spirally into cornets, or is reduced into grains.
IS grains, and is placed in a matrass (See plate 4.) ; the aqua fortis is now to be poured upon in the propor¬tion, by weight, of three parts to two of the silver, and the solution to be assisted the heat of a sand-bath. When no further solution goes on, the aqua fortis tho¬roughly charged with the silver, and to be decanted off; fresh aqua fortis to be added, and to be repeated to third time, as before the gold now to be washed with boiling water, which will make perfectly pure,
the operation has been duly performed, and this gold called gold parting.
Parting Goldfrom Silver, Cementation.
Parting cementation, which an appropriate term, also called parting by concentration, and usually em¬ployed when the quantity of gold so great to that of the silver, as to render a difficult task by aqua fortis. The mixed metal to be cemented to be reduced to plates, as thin as small pieces of money. At the bottom of the crucible, or melting pot, to be laid stratum of cement, composed of four parts of bricks powdered and sifted, one part of green vitriol, e. copperas, calcined to redness, and one part of common salt about the thick¬ness of finger in depth. Upon this stratum layer of plates of the metal to be placed, and then another stratum of cement, and so on till the crucible filled. now to be placed in furnace, or oven, (after
top has been luted on the crucible) and exposed for twenty-four hours, till gradually made red hot, but by no means to be melted. The fire now left to go
out, and the metal permitted to cool, that may be separated from the cement, and boiled repeatedly in large quantities of pure water. This gold afterwards to be tried on touch-stone and not sufficiently purified, the process must be formed second time. By the above method we see how powerfully silver h dissolved by marine acid, when in a state of subtile va¬pour, which is disengaged from the common salt of the cement. Instead of common salt, nitre may be used, as the nitrous acid readily dissolves silver ; but the mixing of common salt and nitre together, is highly injudicious, because the joint acids are able to dissolve some of the gold with the silver. Whatever silver has been separated will now remain in the cement, but it may be freed from this by lead, in the method described in cupeUation.
Parting of Gold from Silver, in the dry Way.
Besides the two former methods of parting, there is a third, which is termed dry parting, or parting by fusion, which is performed by means of sulphur. This dry part¬ing is troublesome, and even expensive, and ought not to be undertaken but when the silver far exceeds the gold, because sulphur will not separate it so easily as aqua fortis, and will, therefore, require a further appli¬cation to cupellation and solution.
Before we treat of silver separately, we shall mention the purification of gold by antimony.
Purification of Gold by Antimony.
Gold is purified from its allays by melting it in a cru¬cible that will hold twice its quantity at least, and throw¬ing upon whilst in fusion, twice its weight of crude antimony. The crucible then to be covered, and the
whole to be kept in melting state for some mi¬
nutes and when the surface sparkles, quickly to be poured into an inverted cone (see plate 4.) which has been previously heated and greased. By striking the cone on the ground, the descent of the metal will be assisted, and will come out, compactly, when cold, by simply
Ti simply inverting it. The compact mass consists of two substances : the upper part is the sulphur of the crude antimony united with the impure allay ; and the lower¬part is the gold united to some of the regulus of an¬timony, proportionable to the quantity of metals which have been separated from the gold, and which are now united with the sulphur of the antimony. This regulus of gold may be separated from the regulus of antimony by simple exposure to a less heat than will melt the gold, because antimony is volatile in such a heat, and is then dissipated. If the gold is not sufficiently purified by this first process, (which is often the case) it must be repeated a second and even a third time. When a part is dissipated, more heat is required to keep the gold in fusion ; therefore the fire must be encreased to¬wards the end of the operation. The purification is completed by means of a little nitre thrown into the crucible, which effectually calcines the remaining regulus of antimony. Sometimes after these operations, the gold is found to be deprived of much of its usual duc¬tility, which, however, is easily restored to it by fusing it with ./nitre</ and ./borax</.
Of silver.
Silver, called ./Luna</ and ./Diana</, by the chemists, is a metal of a white colour, and lively brilliancy. It has neither taste nor smell, when perfectly pure. Its spe-cific gravity although considerable, nearly one half less than that of gold, as loses in the hydrostatic ba¬lance about an eleventh part of its weight. A cubic foot of this metal weighs seven hundred and twenty pounds. The tenacity of silver also very considerable, for
wire of this metal, only one-tenth of an inch in dia¬meter, will sustain weight of two hundred and seventy pounds, without breaking. Although gold exceed
ductility,
ductility, yet it may be drawn into wires as fine as hairs,
and extended into very thin leaves ; so thin, that a grain only may be spread under the hammer, and be made to contain an ounce of water. It is inferior even to copper in hardness and elasticity, and next after it the most sonorous. Under the hammer it acquires a hardness, which it may be deprived of by heating. It seems to be as fixed and indestructible as gold. Kunckel kept silver, as well as gold, in a glass-house furnace
during a month, without alteration. Silver is apt to tarnish, and even to turn black, but it does not lose its property of being brightened to brilliancy. All the strong acids are capable of dissolving but the muriatic and vitriolic are less powerful than the nitric, or aqua fortis.
Silver may be purified from an allay with other inferior metals, by treating with lead, and also with nitre • the former of which methods termed cupellation or re¬
fining, and the latter purification nitre. As we have given description of the one, under the article gold, we shall now proceed to treat briefly of the other.
Purification Silver Kit re.
Silver that to be purified by nitre ought first to be granulated,* and then mixed with a fourth part of its weight of dry nitre, an eighth part of potash, and
little common glass, all in powder. This mixture to be put into good crucible, of such a size as to be only two-thirds filled with and then to be co¬vered with small inverted crucible, with a small hole in the bottom, and luted on fast. Several, thus disposed, may be placed in furnace, to which ready access of air can be admitted, in order to melt the silver. Char-
Granulation easily performed, by pouring, leisurely, the melted metal between the twigs of new birch-broom, whilst they are agitated, pan of water.
coal
coal is now to surround the crucibles even with the tops, but not above them ; and the fire is to be kindled, and the vessels made moderately red, a lighted coal being placed
over the little hole of the inverted crucible. If a shining light be observed round this hole, and a slight hissing noise be heard, the operation proceeds well. Let the
fire be kept up equally till the appearance cease, when it is to be encreased to melt the metal thoroughly, and then removed from the furnace. The larger crucible is to be broken when it is cold, and the silver will be
found at the bottom, covered with a green alkaline scoria. If the metal be not sufficiently pure and ductile, the operation must be again repeated. Some silver is apt to be lost in this operation, by the swelling and detonation of the nitre, which often forces it through the hole in
the upper crucible, unless great care be used ; nevertheless, this method has its advantages, being much more expe¬
ditious than cupellation.
We now proceed to detail some of the various methods that are known and practised by workmen in gold and silver.
To prepare a Crucible, so as not to contract any Gold though
it be for several Hours in the greatest Heat.
Take a good crucible, that will stand the fire, warm it a little, and smear or rub it over with a rhind of bacon, both inside and outside ; then put it in a warm place to dry ; when dry, repeat rubbing it over again as before, and
let it dry : this do for three or four times. This done, warm your crucible again, and smear both out and in¬side, plentifully, with soap then put to dry and before
you use put on charcoal fire, and the soap will burn in flame when burnt out, you may use for melt¬ing gold or silver, and will not attract these metals, as your common crucible will.
Other Receipts for Cements.
Take fine brick-dust one part, and finely pounded salt,; one part ; moisten and mix them with vinegar, and fill a
crucible half full j then stratify plates of gold, or gold coin, with the aforesaid mixture, or paste, and press it close down ; repeat this as you have occasion, and put a thick
laver at top ; then cover and lute the crucible close, that nothing may evaporate : when this is done, fix your cru¬cible upon a high brick, in the middle of the furnace ; give it a violent heat, for twelve hours, and the salt will con¬sume the impurities of the gold, and attract it into the
brick-dust. Or,
Take, in weight, of nitre, of alum, and of sal-ammo¬niac, one part ; two parts of vitriol ; four parts of salt j cither parts of brick-dust, and mix them with vinegar ; stratify this mixture and the gold, as before directed, in the crucible ; cover and lute it well, and give it a vio¬lent fire for an hour or two, and let it cool of itself; but
before it is quite cold, take out the gold, fling it into white- wine vinegar, and boil it therein ; then brush it ; and after you have done this, heat it red hot upon an iron plate. Oi\
Take blood-stone two ounces, rust of iron, calcined vitriol, sal-ammoniac, verdigrise, one ounce of each ; ar¬menian bole, tutty, nitre, alum, a quarter of an ounce of each ; moisten this mixture three or four times with vi¬negar ; let it dry between while ; then grind it fine, and
proceed as directed ; give it a strong fire for three hours, and repeat it three times.
To bring the silver out of the cementing powder, or brick-dust, mix it with glass and granulated lead ; let it melt together ; put it to the test, that test cu- pellation, and you will have the silver again which was in the gold.
To separate Gold and Silver out of the Sweepings.
Take sweepings ; put them into a pan well glazed ; add a proportionable quantity of mercury to them ; mix the dust and mercury, with your hands, well together, till
you think the mercury has extracted all the gold and
silver from the dust; then put the mass into a piece of wash-leather, and wring out the mercury ; what remains in the leather will be like a paste ; put that into an alembic* and drive the mercury from it into a dish with water, which put under the head to receive it ; what remains, put to the test ; refine it with lead, and separate it with aquafortis.
To separate the Goldfrom gilt Copper.
Take four ounces of sulphur, two ounces of sal-am¬moniac, one ounce of nitre, half an ounce of borax ; grind them fine, with strong vinegar, to a paste, which lay thin over the gilded copper; give it a gentle heat, until the paste is burned away, and the copper looks black ; then take it out, and with a knife, or other such instrument, scrape off the gold in a clean dish, and it
will come off very easy.
J J >
Another Method.
Take the root of bertram;* cut it fine ; pour one quart of strong white-wine vinegar upon it ; put it into aboiiing- pot ; cover it with a lid ; lute it well, and let it boil a little ; then take it off the fire, and let it cool. After this, take a copper cup, or any other thing that is gilt ; neal it well ; quench it in that liquid, and the gold will fali off from
* 5M ' *
* Not a commonly known root. Ed. vol. I c the
the copper to the bottom ; wash and then melt in crucible. Or,
Take fine sal-ammoniac two parts, and sulphur one part grind them well together anoint with linseed oil strew the powder upon hold the gilt piece to the fire, over an earthen dish, with water strike with an iron, and the gold will fall off into the dish. Or,
Take nitre and borax, one ounce of each dissolve them in little quantity of water then neal your copper, and quench in this water repeat this several times, and the gold will fall to the bottom.
To separate Copper from Silver, or any other Allay.
Take half an ounce of verditer, or Spanish green white vitriol and sulphur, one ounce of each alum half an ounce boil all together in vinegar, in glass put in your mixt silver this will dissolve and extract the copper, and the silver remain whole.
To extract the Silver out Ring that thick gilded, so
as the Gold may remain intire curious Secret.
Take silver ring that thick gilt make little hole through the gold into the silver then put the ring into aqua fortis in warm place will dissolve the silver, and the gold will remain whole.
To make brittle Gold malleable.
Put gold into crucible, and give brisk fire in wind furnace, or before the bellows when the gold ready to melt, fling gently upon some good, dry, and clear nitre, which will presently flame, and promote the
fusion of the gold, and will spread and cover the gold then
then cast it into an ingot, which before has been warmed and anointed with wax. Or,
A good way to make gold malleable, is this : take human excrements, dry and calcine them in a crucible to a black powder ; when the gold is in fusion, fling some of this
powder upon and give brisk fire when the powder consumed, cast the gold into an ingot, and will be
fine and malleable you extract the salt from the black powder before you use will still have better effect, and that with less quantity.
To make Silver that brittle, pliable.
Take mark of silver, half an ounce of glass, one ounce of nitre, quarter of an ounce of borax, half an ounce of sal gemnice, or rock salt put all this into cru¬
cible, and cover with lesser one that has vent-hole at the bottom, and lute well then give brisk fire, and continue till you think the silver dissolved then
cover the crucible all over with live coals, except the vent¬hole, and leave to cool take off the upper crucible, and you will find therein hanging all the impurities the silver contained, and which occasioned its hardness then melt the silver again in crucible, and throw into half an ounce of tartar finely ground, and, when in fusion, cast
into an ingot, and you will have fine and malleable silver.
To give Gold, Silver, or other Metals, quick fusion.
Take calcined Venetian soap, borax, glass-gall, or Ve¬nice glass, an equal quantity grind and mix well to¬gether this will cause quick fusion. Or,
Take yellow amber, borax, glass-gall and soap, equal quantities grind them together to powder; and what you design to melt, let be done with that composition.
To try whether granulated Silver contains any Gold.
Take some silver grains, and make strokes with them on a touch-stone ; then, with the end of a feather, let fall a drop or two of aqua fortis upon the strokes, and let them continue upon it for a little while ; if it con¬
tains gold, you will see some remains of the strokes, but if not, the strokes will vanish.
To amalgamate Gold, or to mix it with Mercury, which
is of use to Gilders.
Take a pennyweight of fine gold, beat it into very thin small plates ; heat them in a crucible red hot ; then take
it from the fire, and pour upon them eight pennyweights of pure quicksilver ; stir the matter with a little iron rod, and when you see it begin to rise in fumes, which quickly happens, cast your mixture into an earthen pan filled with water, it will coagulate, and become tractable ; wash it several times to take away its blackness ; thus you have an amalgam ; from which separate that mercury which
is not united, by pressing it between your fingers, after
you have wrapt it up in a linen cloth.
X «•
Gilding upon Silver, Brass, Copper, and Iron.
If you would gild over silver, take of the above amal¬gam, and with it rub that which you design to gild, close,
every where, that it may receive gold all over ; then hold it over a charcoal fire, or lay it upon and will cause the quicksilver to fly away after which, you may heighten the colour with gilding wax, as shall be directed.
A par-ticular Secret to gild Silver to the greatest Perfection.
Take crocus veneris* and vinegar, add to them quick¬silver, heat them together, till they come to the consistence of a paste ; with this quicken or anoint the silver you in¬tend to gild, and wherever you quicken, it will turn of a reddish gold colour, which doth not happen when done with quicksilver only, for then it looks white : this is a cu¬rious secret ; you may gild upon this paste with leaf-gold, which otherwise would require to be ground ; it makes the gilding look rich, and of an high colour.
Another advantageous Manner of gilding on Silver.
Take tartar one part, salt two parts ; pour water upon them, and add some steel filings : boil the silver therein until it becomes reddish ; and it will require only the third part of what gold you would otherwise use.
A particular Method of Gilding, which may he done in a
Moment, better than with Quicksilver.
Take the finest gold ; dissolve it in aqua regia f, which has been prepared with salt ; let the aqua regia be evapo-
* Take slips of copper, and quench them in urine ; repeat this until it easily pulverizes. The powder you will find at the bottom of the urine, which workmen term Crocus Veneris.
f Anna repa is a mixture of the nitric and muriatic acids. The proportions vary, according to the nature of the work it is to be em¬ployed in ; some make it of equal parts, whilst others double one or other of the acids, as experience in working has directed them.—Aqua regia may be also made by dissolving in nitrous acid any salt which contains the muriatic acid, viz. common salt, and sal ammoniac. It must be kept in a phial closely flopped, to keep in the suffocating fumes which are constantly rising.
rated to half the quantity ; then put the glass into a damp cellar, on sand, and the gold will over night shoot into crystals, which take out, and let them dissolve again in distilled vinegar ; put it again upon the fire, and let the half thereof evaporate, then put the glass again in the cellar, as before, in moist sand, and over night the gold will shoot into crystals. Dissolve these in rain water ; and evaporate that to half the quantity, and again it will shoot into crystals ; when this is done, take the crystaline gold, grind it to powder with a knife, put that powder into the white of an hard-boiled egg, after the yolk has been taken out ; set it in a cool and damp place, and over night it will dissolve into an oil : and what silver you anoint with
though ever so thin, drying gently, you will find the gilding of perfectly high and fine colour.
Gilding after the Grecian Manner.
Take mercury-sublimate* and sal-ammoniac, of each J '
one ounce make solution thereof in aqua fortis then
dissolve in line gold, beaten very thin let this solution
evaporate over fire until becomes thickish dip in a
silver wire, and comes out black, and, by nealing
in the fire, turns out gilded, fit to be used for gilding silver.
The true Italian gilding.
Take common vitriol four ounces, alum two ounces, white vitriol one ounce, white lead one ounce, salt two handfuls, river water one quart let boil to half the quan¬tity, and let stand until settles and looks clear, then
fit for use.
* Mercury sublimate, orcorrofive sublimate, mercury dissolved by the muriatic acid and, by fire, raised to the top of matrass, or other veffel.
To deaden Quicksilver for Gilding.
Take pure quicksilver, i. e. free from any mixture of lead ; put it into a matrass, and fling into it a handful of fine white salt ; shake it well together, and let it stand for two days ; then pour upon it strong vinegar ; let it rest a
.day, and you will find a good quicksilver for gilding, and very cheap.
To boil Silver white.
First neal your silver on a charcoal fire, till it be¬comes a little reddish : then, having boiled it with an
equal quantity of salt and tartar, powdered, with water, for a quarter of an hour, take it out and scratch-brush
it in clean water ; then take good tartar, tie it up close in a paper, put it in the fire so long until it has done burn¬ing and smoking ; grind it to a fine powder, mix it with clean water into a paste, and with it rub over your silver : this done, neal it again, and quench it in cold water ; brush what remains black upon it with a hair brush ; and boil it for two minutes in tartar water ; then rince in clean water, and, after you have wiped it with a dry rag, your work will be done.
A Gold Powder.
Take leaf-gold, or any other thin beaten gold, to the quantity of a penny-weight, or as much as you please ; dissolve it in twice its weight of aqua regia. Let half the solution evaporate in a sand heat ; then take dried linen rags ; soak them in the remaining liquid ; dry them by a gentle heat ; and burn them on a slow fire, in a crucible ;
the powder will remain at the bottom, and be of a yel¬lowish colour ; and with this the gilding is performed.
Another for Cold Gilding.
Take half a pound of aqua fortis, put into it two
ounces of sal-ammoniac, finely pulverized ; let it dissolve over a fire, and then filtrate it through a paper ; put it into a matrass, with as much fine beaten gold as will weigh two penny-weights ; set it on a slow lire, in order to dissolve the gold into this aqua regia. "When this is done, add to it two ounces of powdered sai-g amine, or rock salt, fine and clear, and let it dissolve upon the fire ; then take fine clean linen rags, each about a quarter of an ounce in weight ; dip them into that liquid, until all the solution is soaked ; and having dried them, burn them to a pow¬der, which preserve for use. When you gild any thing with this powder, let the metal vou intend to gild be boiled and scraped, that it may be clean and fresh ; wet a piece of cork with spittle, or water, and with it take up some of the powder, rubbing the places of the metal you are about to gild, until it is yellow ; after which, brush and
polish it. You may use, instead of cork, a soft leather,
sewed or tied to the round end of a little stick. Or,
e
Take of the finest gold the quantity of two penny¬weights, and dissolve it in aqua regia ; add to this solu¬tion the weight of the gold of refined nitre ; let that also dissolve ; this done, dip a fine little linen rag until it has soaked up all ; dry it gently, and burn it to powder. With this powder, and fresh water, gild your silver, by rubbing it with a cork, or a leather fastened to the nob end of a stick.
Another Powder to gild with.
Take refined gold ; beat it very thin ; make it into
little rolls ; fling it into aqua regia ; put it in a matrass over
a slow fire, until all the gold is dissolved, and the solution is turned of a yellow colour ; then throw into it some pul¬verized nitre, by little and little, (as much as it will con¬sume) : now take some long narrow slips of old fine linen, draw them through the liquid, and when they are thoroughly wet, hang them in the air to dry, in a glass bowl, or a piece of a broken bottle, and, when dry, light them with
a coal, and let them thus, without flaming, consume to ashes. With these ashes you may gild, rubbing it on the silver with a piece of cork. Or,
Take a penny-weight of gold, with an equal weight of nitre, and sal-ammoniac, all which put into a matrass, with three quarts of aqua fortis ; then put the gold, neal- ing hot, into and as soon as the gold dissolved, take some dry linen rags, dip them therein, dry and burn
them, by candle, to tinder, and preserve for use, as has been said above.
A quickening Water
Take one ounce of quicksilver, and as much aquafortis let them be put together into glass, and after the quick¬silver dissolved, add to five ounces of fresh water
warm and will be fit for use. Or,
Take one ounce of aqua fortis put into matrass
add to quarter of an ounce of mercury, and let dis¬solve then take fresh river water, and mix with that in the glass, and make lukewarm let stand close shut up, and you will have good quickening water for gilding.
Another Water-gilding upon Silver.
Take copper-flakes, pour strong vinegar thereon, add to alum and salt, equal quantities of both set them on fire, and when the vinegar boiled to fourth part, throw into what metal you design to gild, and will acquire a copper colour. If you continue boiling will change
into a fine gold colour. This is a fine secret for goldsmiths to gild silver, for the boiling it in that liquid gives the
gilding a high and rich colour.
A Water which will give Silver a Gold Colour.
Take sulphur and nitre, of each an equal quantity; grind them together very fine, and put them into an un¬glazed vessel ; cover and lute it well ; then set it over a slow fire for twenty-four hours, and what you find remaining, put into a strong crucible, and let it dissolve ; then put it into a phial, and whatever silver you anoint with will have gold colour. Or,
Take sulphur half pound, nitre three quarters of pound, mix both together, and grind fine, and proceed as above, or set twenty-four hours on hot ashes then take out and grind again. Of this powder, take one third mix up with three quarterns of running water mix well, and you will have red water, like blood, which will tinge silver, copper, or brass of fine gold co¬lour, after has lain therein ten days.
A Method to work Cup, one side Gold and the other Silver.
Take piece of fine silver flat aud file rough all Qver on one side raise with graver little points upon it. Then take piece of gold in proportion to what thick-ness you would have form exactly to the dimen¬sions of the silver, in flat square neal both the gold and the silver red hot then lay them quick on one another, and with wooden hammer strike them gently together
when thus you have united these two metals, you may make thereof what you please one side will be silver and the other gold.
To adorn Gold, Silver, or Brass, with Embellishments of Glass.
Take fine pulverized Venice glass, of what colour you please ; grind it upon a stone ; temper it with oil ; and melt it over a clear charcoal fire ; it will look fine and beautiful, espechllv if the ornaments are well designed on the metal, previously to covering it with glass.
Of heightening the colour of gold and gilt works.
Unwrought gold and silver want considerably of that lustre and brightness they appear in at goldsmiths shops ; for there they undergo several operations, and are height¬ened by gilding wax, colouring and helling. ; each of which shall be separately explained.
Gilding Wax, nsed for Gold, or gilded IVork.
Take four ounces of clear wax, three-quarters of an ounce of verditer, half an ounce of copper flakes, half an ounce of red chalk, quarter of an ounce of alum ; melt
the wax, and put the other things, finely powdered, into and stir well together let cool and form thereof
round sticks like sealing-wax when you have occasion to make use of first heat your gold, and then rub over with this wax then neal and draw nimbly through boiling hot water and tartar, and will give the gold
deep colour
Take clear wax one pound ; crocus of copper an ounce
and a half; sal-ammoniac, fine terra-verte and alum, one
ounce of each ; red chalk, half an ounce and one drachm ;
crocus martis and tutty, of each half an ounce ; nitre, two
drachms ; mix all these ingredients together, and after you
have pulverized them, stir and mix it well with melted
wax, which being spread over the gilded work, and then
nealed, as has been observed before, it will give the gold
a surprising beauty. Or,
Take two pounds of wax, one pound of red chalk, one
pound of white vitriol, and four ounces of ces iistum. Or,
Take eight ounces of clear wax, one ounce and a half
of terra verte, one ounce »f ces ustum, one ounce of red
chalk, and half an ounce of alum ; dissolve the wax, and
put these ingredients into it ; let it cool ; then form it into
sticks like sealing-wax ; with this, after you have heated
your gilded metal, rub it over ; then burn it off, and it
will give the gold a deep colour.
Nuremberg Gilding-Wax.
Take two pound of wax, two pound and one ounce of red chalk, one ounce of vitriol, half an ounce of ces ustum, three ounces of verdigrise, and half an ounce of borax. Or,
Take four pounds of clear wax, one pound eight ounces of red chalk, one pound eight ounces of white vitriol, fif¬teen ounces of verdigrise, three ounces of borax, and
fifteen ounces of ces ustum ; beat them fine, and mix them together : when the wax is melted, stir it until you per¬ceive it to cool, and then put in the ingredients, and stir them well together : when cold, form them into sticks like sealing-wax.
To make all Metals malleable.
Take mastich, frankincense, myrrh, and borax, of each half an ounce, pulverize and mix them together, and when your metal is melted, fling in itsome of the powder, and you will be surprised at the effect.
How to quicken Brass for gilding.
Dissolve sal-ammoniac in white-wine vinegar, and with it anoint your work ; this will cause itto receive the mercury.
Of several gold colours, whereby gold, or gilt work, after it has been heigtened with gilding-wax, recieves its proper colour
A Silver Gold-Colour, or a Colour for Gilt Silver.
Take one ounce of verdigrise, one ounce of nitre, one ounce of vitriol, half an ounce of sal-ammoniac, half an ounce of borax ; grind them fine ; boil them in half a pint of urine, to half the quantity ; then with a brush dipt in
this liquid, brush over your gilt work ; put it upon a clear charcoal fire, and when you see it turn black, take it off the fire and quench it in urine.
A Green Gold-Colour.
Take two ounces of nitre, two ounces of vitriol, two ounces of verdigrise, and one ounce of sal-ammoniac ;
mix and grind them with vinegar. Or>
Take four ounces of verdigrise, four ounces of sal-am¬
moniac, two ounces of vitriol, two ounces of as ustum, one ounce of nitre ; grind them with vinegar, and colour your gold with it.
A French Gold-Colour.
Take four ounces of salt, two ounces of alum, two ounces of sal-ammoniac, two ounces of as ustum, one
ounce of nitre ; grind them with vinegar. Or,
Take four ounces of sal-ammoniac, four ounces of ver-
digrise, two ounces of nitre, one ounce and a half of clean copper-flakes ; grind them with vinegar.
A fine Gold-Colour.
Take melted nitre, and black vitriol, an equal quan¬tity of each ; let them boil half away in a clean pipkin.
Another Gold-Colour.
Take one ounce of verdigrise, one ounce of sal-am¬moniac, one ounce of red chalk, one ounce of fine salt ; grind all together, and boil them with vinegar. Or,
Take one ounce of nitre, one ounce of verdigrise, one ounce of vitriol, one ounce of sal-ammoniac ; grind each ingredient, separately, in a clean mortar ; then mix and
put them in a clean pan, with water, and boil them nearly half an hour.
A Green Gold-Colour.
Take four ounces of sal-ammoniac, four ounces of verdigrise, two grains of nitre, and grind them in vinegar.
A White
Take two ounces of nitre, one ounce of alum, and one ounce of salt ; pulverize and mix them well together ;
then take a piece of a broken crucible ; put it in the fire,
and let it be red-hot. Wet the work you design to colour^ and roll it in the powder ; then put it on the red-hot piece of crucible, and the colour will boil up ; when it melts, turn the piece of work with your tongs, and when the colour is quite fluid, and is growing yellow, take it out, and lay it upon a clean brick, or anvil, until it is cold. Then take an unglazed pot, or a large crucible ; fill it almost with clean water ; put into it a handful of salt, and the quantity of a filbert of ground tartar, and six or eight drops of aqua fortis ; let them boil ; then put your work into and boil until the dross of the white colour taken off; then scratch-brush it.
To colour an old Gold Chain as were new.
Take urine, and dissolve therein sal-ammoniac boil the gold chain in this, and will have fine colour.
A Green Colour for Gold Chains.
Take four ounces of sal-ammoniac, four ounces ofver- digrise, one ounce and half of nitre, half an ounce of white vitriol make powder thereof, mix with vinegar, and boil your chain in it.
To give Gold high and fine Colour.
Take red calcined vitriol, or colcothar of vitriol, three ounces, sal-ammoniac two ounces, and verdigrise one ounce grind them together and keep them dry. When you would colour your gold, moisten and strew this powder over neal often, and quench in pump-water.
Another fine Colour for Gold.
Take verdigrise, sal-ammoniac, nitre and vitriol, an equal quantity of each grind them well together pour
vinegar upon them grind them again, as painters do their colours, and let them dry then moisten, grind, and dry
them again repeat this for several times then lay up your powder carefully. When you would colour gold, wet
with urine rub with brush fling the above powder upon and lay on red hot coals, and will turn black then quench in urine, and rub with wire brush in tliis manner you may proceed with the other colours.
To bring pale Gold to an high Colour.
Take verdigrise; pour vinegar upon it; stir well; anoint your gold therewith heat in the fire, and quench in urine.
To make Silver yellow throughout, and to give the Co-lour of Gold.
Take common aqua fort dissolve therein as much silver as you please to eight ounces, take four ounces of hepatic aloes, six ounces of turmeric, and two ounces of prepared tutty that has been several times quenched in urine put these to the solution of the silver they will disssolve, but rise up in the glass like spungc, so the glass must be large, to prevent the running over then draw off, and you will have ten ounces of silver, which as
yellow as gold.
N. B. The two ounces increase in the weight, the tutty, will not stand the test, but be lost when melted down with lead, in cupellation.
A Water to give any Metal a Gold Colour.
Take fine sulphur, and pulverize it ; then boil some stale spring, or rain, water ; pour it hot upon the powder, and stir it well together ; boil and put into one ounce of dragon's blood after well boiled, take off and filter through fine cloth put this water into matrass, after you have put in what you design to colour close
well, and boil and the metal will be of fine gold colour.
Another Water wherewith one may tinge any Metal a
Gold Colour. A curious Secret.
Take hepatic aloes, nitre, and Romayi vitriol, each equal quantities distil them with water in an alembic, till all the spirits are extracted will at last yield yellowish
water, which will tinge any sort of metal of gold colour.
To colour Gold.
Take lock of human hair, of about finger thick lay on live coals, and hold the gold with pair of tongs over to receive the fumes thereof.
To give Gold fine and high Colour.
Take one ounce of ./sal-ammoniac</, two ounces of ./copper-flakes</, one ounce of distilled verdigrise grind all well together put the mixture into matrass pour upon
one quart of good distilled white-wine vinegar let thus dry and boil away; then grind fine, strew on a glass
plate, and set cellar, where will turn into an oil vol. i. H this is again to be gently coagulated, and then ground and mixed with sublimate mercury ; put half an ounce of
wrapt up in bees-wax, into the quantity of pound of
gold that in fusion, and will give high and fine colour.
To give gilded Work fine Colour.
Take clean salt and sulphur boil them together, with water, in an egg-shell, after taking away the inside film take care you do not give too much fire to burn the egg¬shell with this liquid wipe over your gilding, and will make of much brighter colour than was before. Or,
Take powder of sulphur, and bruised garlic boil these in urine neal your gold quench therein, and will give fine colour.
To brighten Spots gilding.
Take alum boil in clear water put your work into this will restore the colour again, and remove the spots.
To give old Silver-Lace, or Trimmings, the Beauty and
Colour new.
Take powder of alabaster, or fresh plaster of Paris in powder put dry into pipkin, and let boil as long as
can then take off the fire; when cold, lay your lace upon cloth, and, with comb-brush, take up some of
that powder, and rub therewith both sides, till as bright as you would have afterwards polish with smooth stone. Or,
Take ox-gall, or the gall of large jack, and some water mix together, and with rub your gold or silver, and you will see the colour change to your liking.
Of the hell, or helling of gold
This is the finishing stroke of either gold or gilt work ; and is per¬formed, after it has undergone the operations with the gilding wax and gold colours, as has been shewn in tlie foregoing arti-cles. The following are the different receipts of different mas¬ters. The ingenious and judicious will, by experiments, soon discover which of them is best, and make his choice of such as he approves.
To Hell Gold, or Gilt Work.
Take two ounces of tartar, two ounces of sulphur, and four ounces of salt ; boil this in half water and half urine ; dip your gold, or gilt work, into and will give fine lustre. Or,
Take eight ounces of salt, two ounces of tartar, two ounces of sulphur, half an ounce of alum boil these in water and urine, and draw your work through, and will answer your expectation. Or,
Take eight ounces of sulphur, eight ounces of alum, eight ounces of yellow arsenic, sixteen ounces of tartar," sixteen ounces of salt boil them in water and urine. Or,
Take three ounces of sulphur, one ounce of alum, one ounce of arsenic, half an ounce of turmeric, and half a grain of antimony grind them very finely together then boil them in urine and water, and stir the ingredients gently together boil the mixture little, put the gilded
plate into and boil till the colour bright. Or,
Take eight ounces of yellow arsenic, sixteen ounces of sulphur, sixteen ounces of tartar, sixteen ounces of burnt alum, three ounces and half of salt boil the mixture in urine and water. Or,
Take sifted ashes and antimony finely pulverized; with these make lye, and with brush rub over the gilt silver. Or,
Take one ounce of white tartar, one ounce of grain sulphur, and nine ounces of salt : grind them together like flour ; then take a copper sauce-pan with fresh water, and let the water boil : put into it one grain of crude yel-low arsenic ; take of the ground ingredients three spoon¬fuls, and let it boil ; after that, you may draw your work through and make as high as you will and will come out clear and with fine lustre.
How to take off the Goldfrom Gilt Silver Tankards or Cups.
To take off the gold from such plate, take sal-ammo¬niac one part, nitre half part grind them both to pow¬der wipe over the gilded part with oil strew the powder upon and lay your plate into the fire to heat well then take out hold your plate over an earthen dish, in one hand, and, with the other, beat with an iron the powder will fall into the dish, together with the gold; which you may separate in the manner as has been directed.
Another Method.
Put quicksilver in an earthen dish heat lukewarm
in this turn your silver cup, or other utensil, and the gold
will separate from the silver, and join the quicksilver when you see the gold all come off the plate, take out and pour the quicksilver with the gold, after cold, into another dish any place still retains some gold,
repeat till you perceive no more upon then strain the quicksilver through leather what remains put into retort, on hot sand, or ashes, and force the rest of the mercury from into a receiver with water what left,
melt together, before.
and refine the gold as has been shewn
Take a glass utensil, put aqua-fortis in the quantity whereof must be according to the bigness of your work take no more than one-eighth of an ounce of sal-ammo¬
niac to one ounce of aqua-fortis beat your sal-ammoniac fine put into the aqua-fortis, and set over the fire till grows warm and when you perceive the sal-ammo¬niac to work, then put in the gilded silver, and when you observe your work to become of a black colour, then the
gold taken off of there pretty large quantity of work,, let lie for half an hour, or an hour, before you
take out, which you must do with pair of wooden pliers when taken out, put into clean water then
neal and afterwards boil with tartar repeat this three
times successively, and your silver will look fresh and new.
How to get the Gold out Aqua Fortis.
Take copper bowl, or cup put into glass full of water, and pour in the aqua-fortis which contains gold then add to quarter of an ounce of borax, and boil up let stand all night the morning pour off gently, and the gold will be settled at the bottom dry by
degrees and, when dry, put little borax to and melt
To give Silver Utensils Lustre.
Dissolve alum in strong lye scum carefully then mix up with soap, and wash your silver utensils there¬with, with linen rag.
To separate Gold from gilded Silver, by Cementation. ,
Take red calcined * vitriol, or cokothar, one part, salt, one part, red lead, half a part ; pulverize and mix them all well together ; with this mixed powder cover your gilded silver all over in an earthen pan ; put it into a furnace, and give it a slow fire, to prevent the melting of the silver :
the powder will attract the gold, which you may reduce by melting it with lead, and by separating it by cupellation.
Of several sorts of solder for gold and silver.
Filings-solder for Silver Chain-work.
Melt three parts of fine silver, and one part of brass ; when in fusion, fling into it a little quantity of yellow arsenic. Or,
Take one part of vellow arsenic, and one part of cop¬per, and melt and granulate : of this take one part, and of fine silver four parts ; melt them together ; cast them into an ingot, and, when cold, file to a fine dust.
A Solder for Silver.
Melt two parts of silver ; then put to it one part of thin beaten brass, or tinsel ; but do not keep it too long in fusion, lest the brass should away in fumes.
[marg.]
*The calcination of vitriol performed thus put what quan¬tity you please of green vitriol into an earthen pot, unglazed set the pot over the fire, and boil till the moisture consumed, and the matter turns into greyish mass, drawing towards white this
called white calcined vitriol. If you calcine this white vitriol good while over strong fire, will turn as red as blood this called cokothar. Cokothar of vitriol may be had at the shops.
Another for Coarse Silver.
Four ounces of silver, three ounces of brass, a quarter of an ounce of arsenic ; melt them together, and pour them out quick.
Another Silver Solder.
Melt two ounces of silver, one ounce of tinsel; add to them half an ounce of white arsenic 5 pour it out quick, and it is a very good solder. Or, Melt one ounce of fine silver, and one ounce of thin brass : when both are well melted together, fling one ounce
of white arsenic upon it ; let it melt, stir it well together, and pour it out quickly.
Of good Solder for Gold.
Melt copper and fine silver together, of each one part ; ■of fine gold, two parts. Or,
Take one penny-weight of the same gold your work is of, and allay it with three grains of copper, and three grains of silver.
The Manner and Way of Solderiyig Gold or Silver,
Beat the solder thin, and cut it into little bits, or pal¬lions ; then take the work which is to be soldered, join it
together with fine wire twisted over it ; wet the joinings with a pencil with water, mixed up with borax; then lay the bits, or pallions, of solder upon and strew some
powdered borax over lay the work, be button or
some other small thing, upon large coal, and blow with your blow-pipe through large lamp-flame upon to melt it.
After this, boil the work either in ./alum-water</, or else in aqua-fortis, to clear it from the borax ; dry it on a char¬coal fire ; then file or turn it ; if it be silver, boil it white in the following manner :
Take the work ; lay it on a clear fire, and, when red hot, take it out, and put it by to cool ; in the mean while, set a copper-pan, not tinned, with water upon the fire, into which put one part of fine salt, and one part of tartar ; boil these together, yet not too fiercely, to prevent its boil¬
ing over ; after it is well boiled, lay the work, when it is a little cold, into and let boil about six minutes then take off the fire, take out the work, and put im-mediately into clean water; take out, and scratch
well with wire brush, to clear of the coat then re¬peat this work over again neal once more boil in tartar and salt, and proceed as before then take black burnt tartar, and mix with little water into paste,
with which rub over the work then neal on clear coal fire take out, and brush the work well of the burnt tartar in clean water put once more in the tartar-water in which was boiled, and let boil four minutes then wash in cold water, and dry with clean rag, and
wiilbe of white and beautiful pearl colour.
To Solder Ring set with Stones.
Take large charcoal put two or three penny-weights of silver upon melt with your blow-pipe and the
lamp then, after you have clapped thin pallion of silver solder betwixt the opening of the ring, dip into but as soon as you see the pallion run, take off your ring
instantly.
A Powder for soldering, equal to Borax.
Take the best hard Venice soap scrape as thin as possible let dry, between two papers, in the air then rub it to a powder; put it into an unglazed pipkin; set it on a gentle coal fire, and let degrees, fumigate un-til has no moisture at all then right. This you
may use for all manner of work, and will do, equal to ./Venice borax</.
To melt Moment several sorts Metals, over Table,
Take two ounces of nitre, tartar one ounce, sulphur half an ounce beat mortar to powder then take one ounce of filed metal, (of any sort) mix well to¬gether put into small crucible, or hollow char¬coal light with little splinter, and will melt imme¬diately.
Another Manner doing it.
Take one ounce of nitre, half an ounce of sulphur, and quarter of an ounce of gunpowder; grind them well together, and put half of this powder into small cru¬cible, or, you will, into an egg-shell then put far-thing, or six-pence, or any other metal, upon and, upon
that, put the other half of the powder press down with your finger then set on stone light and will melt immediately.
N. B. gilt cup, or other plate, anointed with salad oil, and this powder flung upon and lighted, takes off the gold, and melts to mass.
To make Aarum Sophisticum, or Mimick Gold.
Take fine distilled verdigrise eight ounces, tutty four ounces, borax twelve ounces, nitre one ounce and half; pulverize, and mix them all together temper them with oil, with wooden spatula, to the con¬sistence of paste; then put crucible into wind-
furnace, heat red hot, and convey your mass into it with a wooden spatula, by little and little ; when all is in, cover it ; fill your furnace with coals all over the cru-cible ; let it stand in a fierce fire, to melt ; let it cool of itself; then break the crucible, and you will find, at the
bottom, a fine metal like gold, weighing about four ounces, out of which you may form and make what you please : it will be as malleable as real gold.
Another.
Take fine and clear wire-copper four ounces ; melt it ; then fling into it one ounce of spelter, i. e. zinc ; stir it well together with an iron spatula ; blow the fire brisk, to bring it into fusion, but, before you pour it out, put in some borax, and it will give it a peculiar beauty ; then cast
it into an ingot ; out of this ingot you may draw wire for chains, and work it in what form or shape you please ; after you have filed and rubbed your work well with tripoli, then give the finishing, with mixture of one grain of tripoli, and six grains of flower of sulphur, put upon
piece of leather rub your work as usual, and will have a fine gold colour.
Another. *
Take spelter one ounce, of the finest and softest cop-per two ounces melt the copper in crucible when
melted, fling into borax two grains, and sal-ammoniac two grains and, lastly, fling in the spelter pour into an
ingot, and you will have fine gold-coloured metal.
To make a curious Yellow-mixed Metal, resembling Gold, and which may be drawn into fine Wire.
Take eight ounces of tartar put into crucible, and neal degrees then take pulverized dry nitre, and finis:
fling it on the red hot tartar, and it will melt into a yellow mass; take it from the fire, and Jet it cool; then take clean copper; keep it in fusion until it is like water, and fling in (to eight ounces of copper) the first mass ; give the crucible a strong reverberatory heat, until in fusion ; then take the best spelter, or zinc, half an ounce, tutty and Vt* nice salqcani* half an ounce ; put it to the melted copper, and presently vou will hear a crackling noise, and see a yellow fume and flame ascend ; stir this copper, and the other ingredients together, with an iron wire, until it is burnt away ; let it stand a little in the flux, and then, after you have rubbed your ingot with wax, pour it in, and it will be so pliable as to be drawn into wire, and of a high gold colour ; you may work, form, finish, and colour it as you do other gold.
Another Method to make a Metal resembling Gold.
Take fine copper filings one pound, fine nitre eight ounces, prepared tutty six ounces, borax six ounces, hep¬atic aloes four ounces ; mix all well together, and incor¬porate the mixture with linseed oil into a mass ; put it into a clean crucible, and cover it at top, a finger's height, with subtilly pulverised Venice glass; lute it well; put it into a wind-furnace ; fill the same with dead coals, and then put live coals upon them, i. e. light the fire from the top, to go downwards ; blow it for an hour, and give it a fierce fire ; then let it cool of itself; take out the crucible, and break and you will find at the bottom very fine metal, like gold this melt again, and add to one pound two ounces of mercury sublimate, and two ounces of pre-pared tutty, both clapped up red sealing-wax stir
well with dry stick then cast into mould, and make of what you please. Or,
An article unknown and probably, of little use in the receipt. Ed.
Take six ounces of distilled verdigrise ; grind it fine in a marble mortar ; beat eight ounces of prepared tutty, four ounces of nitre, and four ounces of borax, into a coarse
powder : moisten them with oil of turnips,* and stir them in an earthen dish, together, until all is well mixed : then put a crucible into a wind-furnace, and, when red hot, con¬vey the said mixture into it with a wooden spatula ; cover it • add more coals, and give a brisk and strong fire all over the crucible. In about half an hour, put a little stick into and try whether the matter be dissolved, and in fusion like water so, then time to pour out but you find still some matter remain, stir about with your stick cover and give brisk fire, until you find
all dissolved then pour out into mortar,' or brass cone, and you will have fine gold-coloured metal.
To make Brass.
Take of copper what quantity you please; add to. third part of powdered lapis calaminaris put them toge¬ther into melting pot, and be in fusion for about an hour
then pour out the brass.
To Silver Copper, or Brass.
Take of fine silver one ounce sal-gemmae, e. rock¬salt, and sal-ammoniac of each six ounces; glass-gall six ounces beat the silver thin, and then put into one ounce of aqua-fortis let dissolve when dissolved, fling a little salt into and the silver will settle like white
powder at the bottom; then pour off that water, and put on fresh repeat until the silver calx has lost all the fla¬
vour of the aqua-fortis dry this, then take the above in-* gredicnts, and grind them well on clean stone when
Common oil will probably do. Ed. [Ed. = editor, note made by]
you have well ground them, mix and grind them and the silver calx together, with a little water, until the mixture is like a thick paste ; put this up in a clean glass, and when you would silver, take care that your metal be riled and
brushed clean ; rub it over with the above matter, and lay it on live coals ; when it has done smoking, scratch it well, and rub it over again with the silver matter ; do this three times successively, and you will have a fine sil-
vering.
Another way.
Take fine silver; dissolve it in aqua-fortis ; then add to it the same quantity of water as you had done of aqua-fortis ; take common salt, and fling it into the mixed waters, and the silver will precipitate to the bot¬tom, like a powder ; when settled, pour off the mixed water, and sweeten this silver calx by pouring fresh water to shifting until all the sharpness re¬moved. Then drain off the water, and let the silver dry of which take quarter of an ounce, white cal¬
cined tartar one ounce, common salt half an ounce then beat and mix them well together, and with aqua¬
fortis grind them upon stone then let them dry, and you have powder ready to silver with. If you would silver either poor silver, copper, or brass, then rub the powder well in, after you have moistened
with water, with piece of cork, to your mind then lay on coal fire until red hot let cool then boil water with tartar and salt and after
boiled, wash in clean water.
What Metals are most proper to incorporate with Silver.
Silver will easily mix and incorporate with fine clean ropper, of each an equal quantity you add more
./copper</ than ./silver</ to your composition, it loses the whiteness, and is not fit to make any utensils with. All other metals are of a contrary nature to silver, as
lead, tin, iron, brass, &c. therefore they are to be avoided. To silver ./Brass</, in Fire.
TAKe calx of fine silver half an ounce, one ounce of sal-ammoniac, three ounces of salt ; mix and grind these well together. When you use grind and temper
together with water, and rub your brass therewith neal brown then quench in water wherein tartar has been dissolved scratch and finish your work by polishing as you see requisite.
A Powder to silver Copper or Brass with, rubbing with the Finger or Thumb.
Dissolve little silver in aqua-fortis add to as much tartar and sal-ammoniac as to make like paste, whereof make little balls dry and pulverize them
you take some of this powder on your wetted thumb,
and rub upon the copper or brass, will give the co¬lour of silver.
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A silvering on Copper.
Dissolve fine silver in aqua-fortis; pour upon pulverized tartar; and then draw your aqua-fortis
clear off, and there remains black matter with this
rub your copper then neal well, and boil in tartar
and salt.
To silver Copper, or Brass, by boiling it.
Take three ounces of salt, twenty-six leaves of silver, a quarter of an ounce of tartar, and half an ounce of alum ; boil these in an earthen pipkin, and stir well toge¬ther ; put what you design to silver into it ; pour water upon and let boil after well boiled, scratch¬brush put in again, and boil then scratch
again, and repeat this until to your mind.
To boil Brass, like Silver.
Take one part of the filings of good pewter add to one part of white tartar, and mix together then take
an unglazed pipkin put these two ingredients, and the brass (which before must be well scratched and cleaned) into and let boil.
To silver Copper, Brass, Steel, or Iron, so as ?iot to come
off, except be made red hot.
Take urine which made in the morning cover and let stand whole month put into an earthen
pot, and let boil skim and when the third part
evaporated, take two pints of urine, one ounce of tartar, and an ounce of gall-stone put in, and let boil once up. This liquid keep clean and you would silver any metal, take brick-dust on wet woollen rag, and rub therewith your iron, or other metal, until clear and line, and put 24 hours in the prepared urine; after¬wards dry and where you design to silver, rub over with quicksilver you must lay on thin, with an iron spatula which has lain two hours in the urine then rub
on with soft woollen rag, and fine bright silvering.
To silver all Sorts of Metals.
Take as much aqna-fortis as you think there is oc¬casion for ; put it in a glass, and set it on hot ashes ; then put in your quantity of silver, which first has been beaten very thin, and cut into little shreds. When your silver is dissolved, take it off the ashes, and mix that liquid with as much white tartar as will make it like a paste : if
you rub brass, copper, or any other metal, with this, it will be like silver.