all the “watery” solutions into a large vessel and mix with a filtered
saturated solution of copperas; this will cause {381} a precipitate of
pure metallic gold to gradually subside; wash it with cold water and
dry in an evaporating dish.
All rags and settlings that are thick should be burnt in a crucible
until a yellow mass is seen; then take this and dissolve it in 2 parts
muriatic acid and 1 part nitric acid. Let it remain in a porcelain
dish until it begins to thicken, and crystals form on the sides. Add a
little nitric acid, and heat until crystals again form. Now take this
and mix with cold water, add a solution of copperas to it and allow it
to settle; pour off the water, and with fresh water wash till quite
free from acid. The gold may then be used again, and if great care is
exercised almost one-half the original quantity may be recovered.
The quantities given in the recipe should produce about 13 to 15 parts
of the liquid gold. It does not in use require any burnishing, and
should be fired at rose-color heat. If desired it can be fluxed with
Venice turpentine, oil of lavender, or almonds.
«Treatment of Brittle Gold.»—I.—Add to every 100 parts, by weight, 5
to 8 parts, by weight, of cupric chloride and melt until the oily
layer which forms has disappeared. Then pour out, and in most cases a
perfectly pliable gold will have been obtained. If this should not be
the case after the first fusion, repeat the operation with the same
quantity of cupric chloride. The cupric chloride must be kept in a
well-closed bottle, made tight with paraffine, and in a dry place.
II.—Pass chlorine gas through the molten gold, by which treatment most
of the gold which has otherwise been set aside as unfit for certain
kinds of work may be redeemed.
«Assaying of Gold.»—To determine the presence of gold in ores, etc.,
mix a small quantity of the finely powdered ore in a flask with an
equal volume of tincture of iodine, shake repeatedly and well, and
leave in contact about 1 hour, with repeated shaking. Next allow the
mixture to deposit and dip a narrow strip of filtering paper into the
solution. Allow the paper to absorb, next to dry; then dip it again
into the solution, repeating this 5 to 6 times, so that the filtering
paper is well saturated and impregnated. The strip is now calcined,
as it were, and the ashes, if gold is present, show a purple color.
The coloring disappears immediately if the ashes are moistened with
bromine water. The same test may also be modified as follows: Cover the
finely pulverized ore with bromine water, shake well and repeatedly
during about 1 hour of the contact, and filter. Now add to the solution
stannic protochloride in solution, whereby, in case gold is present,
a purple color (gold purple of Cassius) will at once appear. In case
the ore to be assayed contains sulphides, it is well to roast the ore
previously, and should it contain lime carbonate, it is advisable to
calcine the ore before in the presence of ammonium carbonate.
«Gold Welding.»—Gold may be welded together with any metal, if the
right methods are employed, but best with copper. Some recipes for
welding agents are here given.
I.—Two parts by weight (16 ounces equal 1 pound) of green vitriol;
1 part by weight (16 ounces equal 1 pound) of saltpeter; 6 parts by
weight (16 ounces equal 1 pound) of common salt; 1 part by weight (16
ounces equal 1 pound) of black manganic oxide or pulverized, and mixed
with 48 parts by weight (16 ounces equal 1 pound) of good welding sand.
II.—Filings of the metal to be used in welding are mixed with melted
borax in the usual proportion. To be applied in the thickness desired.
III.—A mixture of 338 parts of sodium phosphate and 124 parts of
boracic acid is used when the metal is at dark-red heat. The metal is
then to be brought to a bright-red heat, and hammered at the same time.
The metal easily softens at a high temperature, and a wooden mallet
is best. All substances containing carbon should be removed from the
surface, as success depends upon the formation of a fusible copper
phosphate, which dissolves a thin layer of oxide on the surface, and
keeps the latter in good condition for welding.
«To Recover Gold-Leaf Waste.»—To recover the gold from color waste,
gold brushes, rags, etc., they are burned up to ashes. The ashes are
leached with boiling water containing hydrochloric acid. The auriferous
residuum is then boiled with aqua regia (1 part nitric acid and 3 parts
hydrochloric acid), whereby the gold is dissolved and gold chloride
results. After filtration and evaporation to dryness the product is
dissolved in water and precipitated with sulphate of protoxide of iron.
The precipitated gold powder is purified with hydrochloric acid.
«Gold from Acid Coloring Baths.»—I.—Different lots are to be poured
together {382} and the gold in them recovered. The following method
is recommended: Dissolve a handful of phosphate of iron in boiling
water, to which liquor add the coloring baths, whereby small particles
of gold are precipitated. Then draw off the water, being careful not
to dissolve the auriferous sediment at the bottom. Free this from all
traces of acid by washing with plenty of boiling water; it will require
3 or 4 separate washings, with sufficient time between each to allow
the water to cool and the sediment to settle before pouring off the
water. Then dry in an iron vessel by the fire and fuse in a covered
skittlepot with a flux.
II.—The collected old coloring baths are poured into a sufficiently
large pot, an optional quantity of nitro-muriatic acid is added, and
the pot is placed over the fire, during which time the fluid is stirred
with a wooden stick. It is taken from the fire after a while, diluted
largely with rain water and filtered through coarse paper. The gold is
recovered from the filtered solution with a solution of green vitriol
which is stored in air-tight bottles, then freshened with hot water,
and finally smelted with borax and a little saltpeter.
«Parting with Concentrated Sulphuric Acid.»—It is not necessary
scrupulously to observe the exact proportion of the gold to the silver.
After having prepared the auriferous silver, place it in a quantity of
concentrated sulphuric acid contained in a porcelain vessel, and let
it come to a violent boil. When the acid has either become saturated
and will dissolve no more, or when solution is complete, remove the
dissolving vessel from the fire, let it cool, and, for the purpose of
clarifying, pour dilute sulphuric acid into the solution. The dissolved
silver is next carefully decanted from the gold sediment upon the
bottom, another portion of concentrated acid is poured in, and the
gold is well boiled again, as it will still contain traces of silver;
this operation may be repeated as often as is deemed necessary. The
solution, poured into the glass jars, is well diluted with water, and
the silver is then precipitated by placing a sheet of copper in the
solution. The precipitate is then freshened with hot water, which
may also be done by washing upon the filter; the granulated silver
(sulphate of silver) is pressed out in linen, dried and smelted. The
freshened gold, after drying, is first smelted with bisulphate of soda,
in order to convert the last traces of silver into sulphate, and then
smelted with borax and a little saltpeter.
«To Remove Gold from Silver.»—I.—Gold is taken from the surface of
silver by spreading over it a paste, made of powdered sal ammoniac with
aqua fortis and heating it till the matter smokes and is nearly dry,
when the gold may be separated by rubbing it with the scratch brush.
II.—The alloy is to be melted and poured from a height into a vessel of
cold water, to which a rotary motion is imparted, or else it is to be
poured through a broom. By this means the metal is reduced to a fine
granular condition. The metallic substance is then treated with nitric
acid, and gently heated. Nitrate of silver is produced, which can be
reduced by any of the ordinary methods; while metallic gold remains as
a black sediment, which must be washed and melted.
«Simple Specific Gravity Test.»—A certain quantity of the metal is
taken and drawn out into a wire, which is to be exactly of the same
length as one from fine silver; of course, both must have been drawn
through the same hole, silver being nearly 1/2 lighter than gold,
it is natural that the one of fine silver must be lighter, and the
increased weight of the wire under test corresponds to the percentage
of gold contained in it.
«To Make Fat Oil Gold Size.»—First thin up the fat oil with turpentine
to workable condition; then mix a little very finely ground pigment
with the gold size, about as much as in a thin priming coat. Make the
size as nearly gold color as is convenient; chrome yellow tinted with
vermilion is as good as anything for this purpose. Then thin ready for
the brush with turpentine, and it will next be in order to run the size
through a very fine strainer. Add japan, as experience or experiment
may teach, to make it dry tacky about the time the leaf is to be laid.
Dry slowly, because the slower the size dries, the longer it will hold
its proper tackiness when it is once in that condition.
«To Dissolve Copper from Gold Articles.»—Take 2 ounces of
proto-sulphate of iron and dissolve it in 1/2 a pint of water, then
add to it in powder 2 ounces of nitrate of potash; boil the mixture for
some time, and afterwards pour it into a shallow vessel to cool and
crystallize; then to every part of the crystallized salt add 8 ounces
of muriatic acid, and preserve in a bottle for use. Equal parts of the
above preparation and of boiling water is a good proportion to use in
dissolving copper, or 1 part by weight {383} of nitric acid may be used
to 4 parts by weight of boiling water as a substitute.
«GOLD PURPLE.»
I.—The solution of stannous chloride necessary for the preparation of
gold purple is produced by dissolving pure tin in pure hydrochloric
acid (free from iron), in such a manner that some of the tin remains
undissolved, and evaporating the solution, into which a piece of tin is
laid, to crystallization.
II.—Recipe for Pale Purple.—Dissolve 2 parts by weight of tin in
boiling aqua regia, evaporate the solution at a moderate heat until it
becomes solid, dissolve in distilled water and add 2 parts by weight
of a solution of stannous chloride (specific gravity 1.7) dilute with
9,856 parts by weight of water, stir into the liquid a solution of
gold chloride prepared from 0.5 parts by weight of gold and containing
no excess of acid (the latter being brought about by evaporating the
solution of gold chloride to dryness and heating for some time to
about 320° F.). This liquid is dimmed by the admixture of 50 parts by
weight of liquid ammonia which eliminates the purple. The latter is
quickly filtered off, washed out and while still moist rubbed up with
the glass paste. This consists of enamel of lead 20 parts by weight;
quartzose sand, 1 part by weight; red lead, 2 parts by weight; and
calcined borax, 1 part by weight, with silver carbonate, 3 parts by
weight.
III.—Recipe for Dark Gold Purple.—Gold solution of 0.5 parts by weight
of gold, solution of stannous chloride (specific gravity 1.7) 7.5 parts
by weight; thin with 9,856 parts by weight of water, separate the
purple by a few drops of sulphuric acid, wash out the purple and mix
same with enamel of lead 10 parts by weight and silver carbonate, 0.5
parts by weight.
IV.—Recipe for Pink Purple.—Gold solution of 1 part by weight of gold;
solution of 50 parts by weight of alum in 19,712 parts by weight of
water; add 1.5 parts by weight of stannous chloride solution (specific
gravity 1.7) and enough ammonia until no more precipitate is formed;
mix the washed out precipitate, while still moist, with 70 parts by
weight of enamel of lead and 2.5 parts by weight of silver carbonate.
According to the composition of the purple various reds are obtained
in fusing it on; the latter may still be brightened up by a suitable
increase of the flux.
«To Render Pale Gold Darker.»—Take verdigris, 50 parts by weight and
very strong vinegar, 100 parts by weight. Dissolve the verdigris in the
vinegar, rub the pieces with it well, heat them and dip them in liquid
ammonia diluted with water. Repeat the operation if the desired shade
does not appear the first time. Rinse with clean water and dry.
«To Color Gold.»—Gilt objects are improved by boiling in the following
solution: Saltpeter, 2 parts by weight; cooking salt, 1 part by weight;
alum, 1 part by weight; water, 24 parts by weight; hydrochloric acid,
1 part by weight (1.12 specific gravity). In order to impart a rich
appearance to gilt articles, the following paste is applied: Alum, 3
parts by weight; saltpeter, 2 parts by weight; zinc vitriol, 1 part by
weight; cooking salt, 1 part by weight; made into a paste with water.
Next, heat until black, on a hot iron plate, wash with water, scratch
with vinegar and dry after washing.
«Gold-Leaf Striping.»—To secure a good job of gilding depends largely
for its beauty upon the sizing. Take tube chrome yellow ground in
oil, thin with wearing body varnish, and temper it ready for use with
turpentine. Apply in the evening with an ox-tail striper, and let it
stand until the next morning, when, under ordinary circumstances, it
will be ready for the gold leaf, etc. After the gilding is done, let
the job stand 24 hours before varnishing.
«Composition of Aqua Fortis for the Touch-Stone.»—Following are
the three compositions mostly in use: I.—Nitric acid, 30 parts;
hydrochloric acid, 3 parts; distilled water, 20 parts.
II.—Nitric acid, 980 parts by weight; hydrochloric acid, 20 parts by
weight.
III.—Nitric acid, 123 parts by weight; hydrochloric acid, 2 parts by
weight.
«To Remove Soft Solder from Gold.»—Place the work in spirits of salts
(hydrochloric acid) or remove as much as possible with the scraper,
using a gentle heat to remove the solder more easily.
«Tipping Gold Pens.»—Gold pens are usually tipped with iridium. This
is done by soldering very small pieces to the points and filing to the
proper shape.
«To Recognize Whether an Article is Gilt.»—Simply touch the object with
a glass rod previously dipped into a solution of bichloride of copper.
If the article has been gilt the spot touched should remain intact,
while it presents a {384} brown stain if no gold has been deposited on
its surface.
«To Burnish Gilt Work.»—Ale has proved a very good substitute for soap
and water in burnishing gilt as it increases the ease and smoothness
with which it is accomplished. Vinegar is a somewhat poorer substitute
for ale.
«White-Gold Plates Without Solder.»—The gold serving as a background
for white-gold is rolled in the desired dimensions and then made
perfectly even under a powerful press. It is then carefully treated
with a file until a perfectly smooth surface is obtained. After a
white-gold plate of the required thickness has been produced in the
same manner, the surfaces of the two plates to be united are coated
with borax and then pressed together by machine, which causes the
harder metal to be squeezed slightly into the surface of the other,
furnishing a more solid and compact mass. The metals, now partially
united, are firmly fastened together by means of strong iron wire and
a little more borax solution is put on the edges. Then heat to the
temperature necessary for a complete adhesion, but the heat must not
be so great as to cause an alloyage by fusing. The whole is finally
rolled out into the required thickness.
«To Fuse Gold Dust.»—Use such a crucible as is generally used for
melting brass; heat very hot; then add the gold dust mixed with
powdered borax; after some time a scum or slag will be on top, which
may be thickened by the addition of a little lime or bone ash. If the
dust contains any of the more oxidizable metals, add a little niter,
and skim off the slag or scum very carefully; when melted, grasp the
crucible with strong iron tongs, and pour off immediately into molds,
slightly greased. The slag and crucibles may be afterwards pulverized,
and the auriferous matter recovered from the mass through cupellation
by means of lead.
GOLD ALLOYS: See Alloys.
GOLD, EXTRACTION OF, BY AMALGAMATION: See Amalgams.
GOLD LETTERS ON GLASS, CEMENTS FOR AFFIXING: See Adhesives, under
Sign-Letter Cements.
GOLD, REDUCTION OF OLD PHOTOGRAPHIC: See Photography.
GOLD FOIL SUBSTITUTES AND GOLD LEAF: See Metal Foil.
GOLD-LEAF ALLOYS: See Alloys.
GOLD LEAF AND ITS APPLICATION: See Paints.
GOLD PLATING: See Plating.
GOLD, RECOVERY OF WASTE: See Jewelers’ Formulas.
GOLD RENOVATOR: See Cleaning Preparations and Methods.
GOLD, SEPARATION OF PLATINUM FROM: See Platinum.
GOLD SOLDERS: See Solders.
GOLD TESTING: See Jewelers’ Formulas.
GOLD VARNISH: See Varnishes.
GOLDWASSER: See Wines and Liquors.
GONG METAL: See Alloys.
«GRAIN.»
«Formalin Treatment of Seed Grain for Smut.»—Smut is a parasitic
fungus, and springs from a spore (which corresponds to a seed
in higher plants). This germinates when the grain is seeded and,
penetrating the little grain plant when but a few days old, grows up
within the grain stem. After entering the stem there is no evidence
of its presence until the grain begins to head. At this time the smut
plant robs the developing kernels of their nourishment and ripens a
mass of smut spores.
These spores usually ripen before the grain, and are blown about the
field, many spores becoming lodged on the ripening grain kernels. The
wholesale agent of infection is the threshing machine. For this reason
the safest plan is to treat all seed wheat and oats each year.
Secure a 40 per cent solution of formalin (the commercial name for
formaldehyde gas held in a water solution). About 1 ounce is required
for every 5 bushels of grain to be treated. {385}
Clean off a space on the barn floor or sweep a clean space on the hard
level ground and lay a good-sized canvas down, on which to spread out
the wheat. See that the place where the grain is to be treated is
swept clean and thoroughly sprinkled with the formalin solution before
placing the seed grain there.
Prepare the formalin solution immediately before use, as it is
volatile, and if kept may disappear by evaporation.
Use 4 ounces of formalin for 10 gallons of water. This is sufficient
for 600 pounds of grain. Put the solution in a barrel or tub,
thoroughly mixing.
The solution can be applied with the garden sprinkler. Care must be
taken to moisten the grain thoroughly. Sprinkle, stir the grain up
thoroughly and sprinkle again, until every kernel is wet.
After sprinkling, place the grain in a conical pile and cover with
horse-blankets, gunny sacks, etc. The smut that does the damage lies
just under the glume of the oats or on the basal hairs of the wheat.
Covering the treated grain holds the gas from the formalin _within_ the
pile, where it comes in contact with the kernels, killing such smut
spores as may have survived the previous treatment. After the grain has
remained in a covered pile 2 to 4 hours, spread it out again where the
wind can blow over it, to air and dry.
As soon as the grain can be taken in the hand without the kernels
sticking together, it can be sown in the field. The grain may be
treated in the forenoon and seeded in the afternoon.
Since this treatment swells the kernels it hastens germination and
should be done in the spring just before seeding time.
While the copper sulphate or bluestone treatment is valuable in killing
smut, the formalin treatment can be given in less time, is applied so
easily and is so effectual that it is recommended as a sure and ready
means of killing smut in wheat and oats.
GRAINING CRAYONS: See Crayons.
GRAINING COLORS: See Pigments.
GRAINING WITH PAINT: See Paint.
GRAINING, PALISANDER: See Palisander.
GRAPE JUICE, PRESERVATION OF: See Wines and Liquors.
GRAPHITE AS A LUBRICANT: See Lubricants.
«GRAVEL WALKS.»
For cleaning gravel walks any of the following may be used: I.—Gas-tar
liquor.
II.—Rock salt (cattle salt).
III.—Hydrochloric acid.
IV.—Sulphuric acid.
V.—Fresh limewater. The gas-tar liquor must be poured out a few times
in succession, and must not touch the tree roots and borders of the
paths. This medium is cheap. Cattle salt must likewise be thrown out
repeatedly. The use of hydrochloric and sulphuric acids is somewhat
expensive. Mix 60 parts of water with 10 parts of unslaked lime and
1 part of sulphuric acid in a kettle, and sprinkle the hot or cold
mixture on the walks by means of a watering pot. If limewater is used
alone it must be fresh—1 part of unslaked lime in 10 parts of water.
«GRAVERS:»
«To Prepare Gravers for Bright-Cutting.»—Set the gravers after the
sharpening on the oilstone on high-grade emery (tripoli) paper. Next,
hone them further on the rouge leather, but without tearing threads
from it. In this manner the silver and aluminum engravers grind their
gravers. A subsequent whetting of the graver on the touchstone is not
advisable, since it is too easily injured thereby. A graver prepared as
described gives excellent bright engraving and never fails.
In all bright-cutting the graver must be highly polished; but when
bright-cutting aluminum a lubricant like coal-oil or vaseline is
generally employed with the polished tool; a mixture of vaseline and
benzine is also used for this purpose. Another formula which may be
recommended for bright-cutting aluminum is composed of the following
ingredients: Mix 4 parts of oil of turpentine and 1 part of rum with
1 ounce of stearine. Immerse the graver in any of the mixtures before
making the bright-cut.
GREASES: See Lubricants.
GREASE ERADICATORS: See Cleaning Preparations and Methods. {386}
GREASE PAINTS: See Cosmetics.
GREEN, TO DISTINGUISH BLUE FROM, AT NIGHT: See Blue.
GREEN GILDING: See Plating.
GRENADES: See Fire Extinguishers.
GRINDING: See Tool Setting.
GRINDER DISK CEMENT, SUBSTITUTE FOR: See Adhesives.
«GRINDSTONES:»
«To Mend Grindstones.»—The mending of defective places in grindstones
is best done with a mass consisting of earth-wax (so-called
stone-pitch), 5 parts, by weight; tar, 1 part; and powdered sandstone
or cement, 3 parts, which is heated to the boiling point and well
stirred together. Before pouring in the mass the places to be mended
must be heated by laying red-hot pieces of iron on them. The substance
is, in a tough state, poured into the hollows of the stone, and the
pouring must be continued, when it commences to solidify, until even
with the surface.
«Treatment of the Grindstone.»—The stone should not be left with the
lower part in the water. This will render it brittle at this spot,
causing it to wear off more quickly and thus lose its circularity. It
is best to moisten the stone only when in use, drop by drop from a
vessel fixed above it and to keep it quite dry otherwise. If the stone
is no longer round, it should be made so again by turning by means of
a piece of gas pipe or careful trimming, otherwise it will commence to
jump, thus becoming useless. It is important to clean all tools and
articles before grinding, carefully removing all grease, fat, etc.,
as the pores of the stone become clogged with these impurities, which
destroy its grain and diminish its strength. Should one side of the
grindstone be lighter, this irregularity can be equalized by affixing
pieces of lead, so as to obtain a uniform motion of the stone. It is
essential that the stone should be firm on the axis and not move to and
fro in the bearings.