The richness in gold of any substance, whether liquid or solid, when the
quantity is small (and indeed in all other cases), is most simply and
economically performed by the common method of chemical analysis. The gold
may be thrown down from its solution by adding a solution of protosulphate
of iron; the precipitate, after being washed, dried, and gently heated,
may be weighed as pure gold.
_Pois., &c._ The soluble preparations of gold (chlorides) are violent
poisons. The symptoms resemble those occasioned by corrosive sublimate,
but are somewhat less violent. Metallic gold in a minute state of division
is also capable of producing very unpleasant consequences, and even
endangering life. The antidote is iron filings or a solution of sulphate
of iron, given conjointly with an emetic.
_Uses._ The numerous applications of gold in the arts and the daily
transactions of life need only be alluded to here. In _medicine_, gold has
been given in the form of powder, in scrofula and syphilis, by Chrestein,
Niel, and others, with apparent advantage.--_Dose_, 1/4 gr. to 1 gr., 3 or
4 times a day, in pills, or as a friction on the tongue and gums. An
ointment made of 1 gr. of powdered gold and 30 gr. of lard has been
applied by Niel to the skin deprived of the epidermis (endermically) in
the above diseases.
The more important chemical compounds containing gold, the alloys and
commercial forms of the metal, together with certain factitious substances
popularly called 'gold', are noticed in alphabetical order _below_:--
=Gold, Alloys and Preparations of:--=
=Gold, Dutch.= MANNHEIM GOLD, MOSAIC G., OR-MOLU, PINCHBECK, PRINCE'S
METAL, RED BRASS, SIMILOR, TOMBAC. These names are applied to several
varieties of fine gold-coloured brass, differing slightly in tint and in
the proportions of copper and zinc. The terms tombac, prince's metal,
similor, and Mannheim gold, are used by some authors to designate alloys
consisting of about 85% of copper and 15% of zinc; whereas, according to
other authors, prince's metal and Mannheim gold are synonymous, and are
composed of 75% copper and 25% zinc; according to another author, similor
consists of about 71-1/2% copper and 28-1/2% zinc, and Mannheim gold of
80% copper and 20% zinc; and, again, according to another author, similor
and Mannheim gold are synonymous, and are applied to alloys of copper
containing from 10 to 12% zinc and from 6 to 8% tin. Seeing that such
inextricable confusion exists in the employment of the terms above
mentioned, it is desirable to discard them altogether. At the celebrated
works of Hegermühl, near Potsdam, the proportions copper, 11 parts, to
zinc, 2 parts, are employed to produce a metal which is afterwards rolled
into sheets for the purpose of making Dutch leaf-gold. This alloy has a
very rich, deep gold colour. Its malleability is so remarkable that it may
be beaten out into leaves not exceeding 1/52900 inch in thickness.
=Gold, Facti''tious.= _Prep._ From copper, 16 parts; platinum, 7 parts;
zinc, 1 part; fused together. This alloy resembles in colour gold of 16
carats fine, or 2/3, and will resist the action of nitric acid, unless
very concentrated and boiling.
=Gold, Grain.= _Syn._ AURUM GRANULATUM, L. _Prep._ From cupelled gold, 1
part; silver, 3 parts; melted together, and poured in a small stream into
water; the silver being afterwards dissolved out by digestion in boiling
nitric acid, and the grains, after being well washed in water, heated to
redness in a crucible or cupel. Used to make preparations of gold.
=Gold, Jew'eller's.= This term is applied to alloys of gold used for
trinkets and inferior articles of jewelry, ranging from 3 or 4 carats fine
upwards; or which are too inferior to receive the 'Hall mark'. The lowest
alloy of this class is formed of copper, 16 parts; silver, 1 to 1-1/2
part; gold, 2 to 3 parts; melted together. This is worth only from 8_s._
6_d._ to 9_s._ 6_d._ the oz.
It has recently been found that gold of the quality of 12 carats, or less,
if alloyed with zinc instead of the proper quantity of silver, presents a
colour very nearly equal to that of a metal at least 2-1/2 to 3 carats
higher, or of 8_s._ or 10_s._ an ounce more value; and the consequence has
been that a large quantity of jewellery has been made of gold alloyed in
this manner; and the same has been purchased by some shopkeepers, very
much to their own loss as well as that of the public; inasmuch as a
galvanic action is produced, after a time, upon gold so alloyed, by means
of which the metal is split into several pieces, and the articles rendered
perfectly useless.
=Gold, Leaf.= _Syn._ GOLD-LEAF. Gold reduced to leaves by hammering it
between thin animal membrane. Its preparation constitutes the trade of the
goldbeater. These leaves are only 1/28200 of an inch in thickness. Gilt
silver is hammered in the same way, but the leaves are thicker. The latter
is called party gold. Both are used by artists and gilders, and by
druggists to gild pills, &c.
=Gold, Powdered.= _Syn._ DIVIDED GOLD, GILDING POWDER, GOLD BRONZE, GOLD
COLOUR; AURI PULVIS. _Prep._ Gold, 1 part; mercury, 7 parts; form an
amalgam, and expose it to heat until all the mercury is volatilised; or
the mercury may be dissolved out with hot nitric acid. In either case the
residuum is to be powdered, washed, and dried. If the quantity operated on
is considerable, the process should be so conducted as to save the
mercury.
From gold leaf and honey ground together, as the last, by means of a stone
and muller. This is the plan commonly adopted in the small way by artists.
From a solution of gold in aqua regia precipitated by protosulphate of
iron, the resulting powder being washed, dried, and gently heated, This
gives pure gold.
_Uses, &c._ Powdered gold is employed in gilding by japanners and by
artists. It is either sold in powder (gold in powder), or made up into
shells (gold in shells). Its use in medicine has been already noticed.
=Gold, Standard.= The standard gold of this country is an alloy of pure
gold, 11 parts, with pure copper, 1 part. Formerly the alloy consisted
partly of silver, as found in some of the older coins now in circulation.
It is often spoken of as 22 carats fine.
=Gold, Chlorides of:=
1. =Monochloride.= AuCl. _Syn._ AUROUS CHLORIDE, PROTOCHLORIDE OF GOLD. A
yellowish-white mass, formed when a solution of trichloride of gold is
evaporated to dryness, and the residuum is exposed to a heat of about 440°
Fahr., until fumes of chlorine cease to be evolved. It is insoluble in
water, which decomposes it, slowly when cold, but rapidly by the aid of
heat, into metallic gold and the trichloride.
2. =Trichloride.= AuCl_{3}. _Syn._ AURIC CHLORIDE, TERCHLORIDE OF GOLD,
TRICHLORIDE OF GOLD, AURI CHLORIDUM. _Prep._ Gold, 1 part, dissolved by
aid of heat in nitro-hydrochloric acid, 8 parts, and evaporated down to
near dryness, and allowed to crystallise.
_Prop._ Orange-red crystalline needles, or ruby-red prismatic crystals;
deliquescent; soluble in water, ether, and alcohol, forming a deep-yellow
solution; at the heat of 500° Fahr. it suffers decomposition, chlorine
being given off and pure gold left behind. It is reduced by ferrous
sulphate, oxalic, sulphurous, formic and phosphorous acids, as well as by
most of the metals, to metallic gold. It combines with several of the
metallic chlorides, forming a series of double salts, which are mostly
yellow when in crystals, and red when deprived of water.
_Uses, &c._ It has been employed by Duportal, Chrestien, Niel, Cullerier,
Legrand, and others, as a substitute for mercury, in scrofula,
bronchocele, chronic skin diseases, &c.; also as a caustic.--_Dose_, 1/20
gr., dissolved in distilled water, or made into a pill with starch; or, in
frictions on the gums, in quantities of 1/16 to 1/10 gr. Its most
important use, however, is as a reagent in photography, large quantities
being manufactured for use as a chief agent in toning photographic prints.
To some extent it is also used for electro-gilding, and mixed with excess
of bicarbonate of potassium, it forms a good yielding solution for small
articles of copper. These are to be first cleaned with dilute nitric acid,
and then boiled for some time in the mixture.
The above is the salt generally referred to under the name of the
'chloride of gold,' or in commerce occasionally as the 'muriate of gold.'
=Gold, Chloride of, and Sodium.= AuCl_{3}. NaCl. 2Aq. _Syn._ AUROCHLORIDE
OF SODIUM; SODII AUROCHLORIDUM. _Prep._ Auric chloride, 85 parts; chloride
of sodium, 16 parts; dissolve in a little distilled water, evaporate until
a pellicle forms, then put it aside to crystallise. It forms beautiful
orange-coloured rhombic prisms.
_Dose, &c._ 1/20 to 1/12 gr., made into a pill with starch or lycopodium,
in the same cases in which the terchloride is ordered. Mixed with 2 or 3
times its weight of orris powder, it has been used in frictions on the
tongue and gums, and an ointment made with 1 gr. of the salt, mixed with
36 gr. of lard, has been applied to the skin deprived of the epidermis by
a blister.
=Gold, Cyanide of.= AuCy_{3}. _Syn._ AURIC CYANIDE. _Prep._ Add a solution
of pure cyanide of potassium to a solution of pure auric chloride as long
as a precipitate forms, carefully avoiding any excess; wash, and dry the
precipitate.
_Prop., Uses, &c._ The salt is a pale-yellow powder, insoluble in water,
but very soluble in a solution of cyanide of potassium, forming the double
cyanide of gold and potassium so largely used in the electrotype process.
Cyanide of gold is employed to a certain extent in medicine.--_Dose_, 1/12
to 1/10 gr., made into a pill, in the usual cases in which gold is
administered. The first formula is essentially similar to that of the
French Codex.
=Gold, Extraction of, by Sodium Amalgam.= (Crookes' Method, Patented.) In
the extraction of gold by amalgamation serious difficulties are often
occurring through the 'flouring' or 'sickening' of the mercury employed,
and the prevention of the amalgamation by a coating of tarnish on the
gold. So much is this the case that losses of from 30 to 60 per cent. of
the gold are usually incurred, and, in many cases a still more serious
loss of mercury.
When certain minerals, as tellurium compounds, pyrites, &c., occur in the
gold ore, the mercury is apt, on trituration, to become subdivided into
excessively minute globules, which, owing to their tarnished condition,
refuse to unite, and are consequently washed away, it being almost
impossible to separate them from the heavier portions of the ore. This is
technically called 'flouring,' 'granulating,' &c. Besides this, certain of
these minerals affect the mercury in another way, that is, by 'sickening'
it, or causing it to lose its bright surface and fluidity, and prevents
its amalgamating with the gold. Besides the inconvenience and loss thus
caused, a further loss of gold takes place from the inability of the
ordinary mercury to touch or amalgamate tarnished gold, unless it is
ground with it, for a more lengthy period than is found practicable in
most cases.
Mr Crookes, F.R.S., has, by means of the addition of a certain proportion
of sodium, in the form of an amalgam, to the mercury, effectually
prevented this serious loss of gold and mercury. By adding certain
quantities of amalgams B and C, an amount which, differing from each ore,
is ascertained by experiment, the 'flouring' and 'sickening' of the
mercury is effectually prevented, the mercury remaining throughout in the
best condition. The addition of about one tenth per-centage of amalgam A,
at intervals of some hours, increases most powerfully the affinity of the
mercury for the precious metals, and secures a more thorough amalgamation.
This invention has met with general approval, and experiments conducted at
many mines show its great practical value, giving an increase of from 5 to
30 per cent. in the yield of gold, and, in fact, with many pyrites that
yielded no gold to the ordinary amalgamation process, gave a considerable
yield of gold to the sodium amalgamation process. This has led to its use
in most mines, both silver and gold, in America.
=Gold, Iodide of.= AuL_{3}. _Syn._ AURIC IODIDE, TRI-IODIDE OF GOLD, GOLD
TERIODIDE, AURI IODUM. _Prep._ Add a solution of trichloride of gold to
one of iodide of potassium. The resulting precipitate is at first
redissolved on agitation, a soluble double iodide being formed;
subsequently the iodide of gold is precipitated, leaving the supernatant
liquor free of colour.
_Prop., Uses, &c._ A dark-green powder, easily soluble in hydriodic acid.
It is occasionally employed as a medicine, and, like other preparations of
gold, is of an alterative character.--_Dose._ About 1/16th of a grain.
=Gold, Oxides of=:--
1. =Monoxide.= Au_{2}O. _Syn._ AUROUS OXIDE, PROTOXIDE OF GOLD. _Prep._
Formed by treating the aurous chloride with strong potassium hydrate.
Green powder, somewhat soluble in potassium hydrate solution, and readily
decomposing into metallic gold and auric oxide.
2. =Trioxide.= Au_{2}O_{3}. _Syn._ AURIC OXIDE, OXIDE OF GOLD, PEROXIDE OF
GOLD, AURIC ACID, AURI OXIDUM. _Prep._ Magnesic oxide, 4 parts; auric
chloride, 1 part; water, 40 parts; mix, boil, and wash the precipitate
with water, dilute nitric acid, and again with water. It must be dried in
the shade.
Reddish-yellow powder, easily decomposed by heat; readily soluble in
hydrochloric and hydrobromic acids and strong nitric acid, but insoluble
in water and the other acids. Forms unstable salts with the alkalies.
_Uses, &c._ Trioxide of gold has been given in scrofula, &c., in doses of
1/12 to 1/2 gr., or 1 gr., in scrofula, syphilis, &c., made into a pill
with extract of mezereon.
=Gold, Ammoni'uret of*.= _Syn._ AURATE OF AMMONIA, BERTHOLLET'S
FULMINATING GOLD; AURUM AMMONIATUM, AMMONIÆ AURAS, L. _Prep._ By adding
ammonia to a solution of gold in aqua regia (trichloride), as long as a
reddish-yellow precipitate (fulminating gold) forms; the latter must be
collected, washed, and dried with the greatest possible caution.
_Obs._ Ammonia fails to precipitate trioxide of gold from solutions which
are not tolerably concentrated, and in those containing free acid or
ammoniacal salts the precipitate only forms upon boiling the solution.
Before adding the ammonia, it is, therefore, proper to drive off the
excess of acid, if any, by the application of heat. See FULMINATING
COMPOUNDS.
=Gold, Sul'phide of.= Au_{2}S_{3}. _Syn._ SULPHURET OF GOLD, TERSULPHURET
OF G.; AURI SULPHURETUM, L. _Prep._ Transmit a current of sulphuretted
hydrogen gas through a solution of terchloride of gold in water; or add
hydrosulphuret of ammonia to the same solution; collect the precipitate,
wash it with cold distilled water, and dry it in the shade.
=GOLD DETER'GENT.= _Prep._ (Upton.) Take quicklime, 1 oz.; sprinkle it
with a little hot water to slake it, then gradually add boiling water, 1
pint, so as to form a milk. Next dissolve pearlash, 2 oz., in boiling
water, 1-1/2 pint; mix the two solutions, cover up the vessel, agitate
occasionally for an hour, allow it to settle, decant the clear, put it
into flat half-pint bottles, and well cork them down.
_Use._ To clean gilding, &c., either alone or diluted with water. It is
applied with a soft sponge, and then washed off with clean water. It is
essentially a weak solution of potassa, and may be extemporaneously
prepared by diluting solution of potassa (Ph. L.) with about 5 times its
volume.
=GOLD SHELLS.= Gold leaf or powdered gold ground up with gum-water, and
spread upon the insides of shells. Used by artists.
=GOLD SIZE.= _Syn._ GILDING SIZE, GILDER'S S., GOLD COLOUR. _Prep._ 1.
(OIL SIZE.) Drying or boiled oil thickened with yellow ochre or calcined
red ochre, and carefully reduced to the utmost smoothness by grinding. It
is thinned with oil of turpentine. Improves by age. Used for oil gilding.
2. (WATER SIZE.) Parchment or isinglass size, mixed with finely ground
yellow ochre. Used in burnished or distemper gilding.
=GOLD-BEAT'ER'S SKIN= is prepared from the peritoneal membrane of the
cæcum of the ox. It is used to separate the leaves of gold whilst under
the hammer, as a nearly invisible defensive dressing for cuts, as a fabric
for court plaster, &c.
=GOLDEN SEAL.= See HYDRASTIS CANADENSIS.
=GONG METAL.= See BELL METAL.
=GONIOM'ETRY.= The art of measuring the angles of crystals, by means of a
GONIOMETER; a most important matter in _chemistry_ and _mineralogy_. The
only accurate and simple instrument of this kind is the REFLECTING
GONIOMETER invented by Dr Wollaston. Facility in using this instrument is
readily acquired by a few trials.
=GOOSE.= This bird, the _Anser domesticus_, is a favourite article of food
almost everywhere, and may fairly claim a similar position amongst poultry
to that occupied by "good Sir Loin" among joints of meat. The vulgar
inuendos occasionally heard to its prejudice should be directed against
the cook rather than the bird, as it is only when it is unskilfully
dressed and too highly seasoned that it is apt to disagree with that
"irascible member of the interior," a delicate or overloaded stomach.
Undue susceptibility in that quarter may, however, be generally allayed by
an oblation, in the shape of a little '_eau de vie_,' used as sauce or
gravy. Formerly, almost miraculous virtues were attributed to this bird.
Its flesh was said to promote longevity, to cure hydrophobia, and to be
aphrodisiac. The fat (GOOSE GREASE; ADEPS ANSERIS), mixed with honey, was
supposed to be "good against the bitings of a mad dog." At the present day
it is occasionally used in clysters, and, when scented, as a pomade to
make the hair grow, for which purpose it is said to be superior to bear's
grease. In quantity it is an emetic of very easy action. The large
feathers of the wings (quills) are used for writing. The small feathers
form the common stuffing of our beds.
=GOOSE'BERRY.= The fruit or berry of _Ribes grossularis_. Unripe fruit,
cold and acidulous; ripe fruit, wholesome and slightly laxative; but the
seeds and skins should not be eaten, as they are very indigestible; the
juice of the green fruit is made into wine (ENGLISH CHAMPAGNE); the seeds,
washed and roasted, were formerly used as a substitute for coffee
(GOOSEBERRY COFFEE). Gooseberries are preserved by simply bottling them,
and keeping them in a very cold place. See CHEESE, FOOL, FRUIT, &c.
=GOULARD.= _Syn._ GOULARD'S EXTRACT. See SOLUTION OF DIACETATE OF LEAD.
=GOUT.= _Syn._ ARTHRITIS, L. A painful disease that chiefly attacks the
male sex, particularly those of a corpulent habit and robust frame.
Persons who live temperately and take much exercise are seldom troubled
with gout. Indolence, inactivity, luxurious habits of life, and free
living, are the chief exciting causes of this disease; but excessive
study, grief, watchfulness, exposure to cold, and the too free use of
acidulous liquors, also occasionally bring it on. In some persons it is an
hereditary disease.
_Symp._ Gout is generally preceded by unusual chilliness of the feet and
legs, and a numbness or a sensation of prickling along the lower
extremities; the appetite fails, flatulency, indigestion, torpor, and
languor ensue, and extreme lassitude and fatigue follow the least bodily
exercise; the bowels become costive, and the urine pallid. The fits
usually come on in the night; the patient is awakened by the severity of
the pain, generally in the first joint of the great toe, or occasionally
in the heel, whole foot, or calf of the leg. The pain resembles that of a
dislocated joint, accompanied by a sensation resembling the effusion of
cold water; the pain increases, rigors and febrile symptoms ensue,
accompanied with local throbbing and inflammation. Sometimes both feet and
legs are attacked; at others, only one. Towards morning the patient
generally falls asleep, and sinks into a state of copious perspiration,
from which he awakes comparatively recovered. This constitutes what is
called a 'fit of gout.' These fits or paroxysms are apt to return at
intervals, commonly every evening, with more or less violence; and when
frequent, the disease usually extends its action, the joints become
affected, and concretions of a chalky nature (chalk stones, gout stones)
are formed upon them, and they become stiff and nearly immovable.
_Treat._ A plain or vegetable diet, moderate exercise, and the use of warm
laxatives, gentle tonics, diaphoretics, and diuretics, are among the best
preventives. The moderate use of alkaline remedies, as potassa and
magnesia, has also been recommended. To relieve the fit of gout, or to
check it at its commencement, the affusion of cold water will be often
found effective. The use of the '_eau médicinale_', or the '_vinum
colchici_' of the Pharmacop[oe]ia, may also be had recourse to; a due dose
of which taken at bedtime will frequently carry off the paroxysm, and
nearly always mitigate the symptoms. The effect of the above remedies do
not greatly differ from each other. The action of both medicines is
accompanied with great languor, and a deadly nausea or sickness, which
terminates in vomiting or a discharge from the bowels, or both. These
symptoms have often reached an alarming extent, and in some constitutions
follow even a moderate dose. This method of cure should not, therefore, be
unadvisedly and incautiously adopted.
Another remedy which has been recommended for gout is lemon juice, but
experience has proved that this agent is not to be depended on. The dose
proposed by Dr O. Rees, who originated this treatment, was 2 or 3 fl. oz.,
twice or thrice a day.
To ensure the efficacy of lemon juice, it must be expressed from the
fruit into the glass shortly before being taken. That purchased at the
shops is generally stale and disagreeable, and is often worse than
useless. In some cases it is advisable to take the juice undiluted, but
the more common practice is to mix it with about an equal quantity of
water. See RHEUMATISM, COLCHICUM, DRAUGHT (Anti-arthritic), LEMON JUICE,
VINEGAR OF COLCHICUM, WINE OF COLCHICUM, &c.
=Gout Cor'dial.= _Prep._ Rhubarb, senna, coriander seed, sweet-fennel
seed, and cochineal, of each 2 oz.; liquorice root and saffron, of each 1
oz.; raisins, 2-1/2 lbs.; rectified spirit of wine, 2 gals.; digest for 14
days, press, and filter. Used in gout and rheumatism. Aromatic and
slightly laxative.--_Dose_, 1 to 3 table-spoonfuls.
=Gout Med'icine.= (Duncan's.) A mixture of wine of colchicum, wine of
opium, and tincture of saffron.
=Gout Rem'edy.= (Alexander's.) According to Dr Paris, this
contains--aniseed, cumin seed, ginger, hermodactyles, pepper, and
scammony.
=Gout Specific.= (Murray's.) A mixture of iodide of potassium, sulphate of
magnesia, and wine of colchicum, disguised with an aromatic tincture.
=GOUTTES AMERES.= [Fr.] See DROPS (Bitter).
=GRAD'UATOR.= See VINEGAR.
=GRAFTING COM'POST.= Clay tempered with water, to which a little linseed
oil is sometimes added. Used to cover the joint formed by the scion and
stock in grafting.
=GRAINS OF HEALTH, Dr Franck's--Gesundheitspillen--Grains de Santé, ou
Grains de Vie=, du Docteur Franck. Silvered pills, containing 1 part
gamboge and 4 parts aloes. (Hager.)
=GRAINS OF PAR'ADISE.= _Syn._ GUINEA GRAINS, MELEGUETTA PEPPER. The seeds
of the _Ammomum meleguetta_. Grains of paradise are hot, acrid, and
aromatic, and in general properties similar to the other peppers. In some
parts of the world they are used as a condiment. They are principally
employed in these countries to impart a false strength to wine, beer,
spirits, and vinegar.
=GRANIL'LA.= A small inferior variety of cochineal (which _see_).
=GRANULA'TION.= The act or process of forming, or breaking into, grains or
small masses.
The granulation of MEDICINES has of late years received considerable
attention from both foreign and British pharmaceutists. In France,
granulated powders (POUDRES GRANULÉES) are coming into general use in
place of impalpable powders, the most unpleasant of all forms of medicine.
The French process consists in enveloping the particles of medicines in
syrup by means of heat and constant stirring. Mr Banner, of Liverpool, has
lately introduced a method of granulating medicines far preferable to that
of the French pharmaceutists. The powder to be granulated is placed in a
mortar, and mucilage of gum acacia is gradually added until a crumbly mass
is made; this is then rubbed through a wire sieve (about 12 meshes to the
inch), and the granules produced are spread out on paper, and left to dry
spontaneously, or they are placed in a copper pan, and kept in constant
motion over a stove until dry; when perfectly dry, they are placed in a
mortar, and sufficient quantity of strong tincture of tolu (3 dr. to 1
oz.) is added to them, until by constant stirring they all appear glossy
and shining; they are then dried again by a gentle heat, being kept in
constant motion. The granules thus formed keep well, are tasteless, and
are much more elegant and agreeable preparations than pills or ordinary
powders. Many saline substances are granulated by the simple process of
dissolving the salt in water, and evaporating to dryness with constant
stirring.
METALS are granulated (reduced to drops, grains, or coarse powder) by
pouring them, in the melted state, into water. In many cases they are
allowed to run through the holes of a species of colander or sieve to
produce minute division; and in order to render the drops spherical, they
are allowed to fall from a sufficient height to permit of their acquiring
the solid state before striking the water. Lead shot is made in this way.
Shot towers are often upwards of 100 feet in height. See COPPER,
GUNPOWDER, POWDER, ZINC, &c.
=GRAPES.= _Syn._ UVÆ, L. The fruit of _Vitis vinifera_, or the common
grape vine. Ripe grapes are cooling and antiseptic, and in large
quantities diuretic and laxative. They are very useful in bilious
affections and dyspepsia, and in all febrile, putrid, and inflammatory
complaints. The skin and seed, which are indigestible, should be rejected.
"Grapes which contain a large quantity of sugar are, if taken without the
husks, the safest and most nutritive of summer fruits." (Cullen.) "The
subjects of pulmonary affections, who pass the summer in Switzerland, may
try the effects of a course of grapes, '_cure de raisins_,' a remedy held
in high estimation in several parts of the Continent." (Sir J. Clark.)
Grapes, in bunches are preserved by wrapping them in silver paper, and
packing them in dry bran. Each bunch is suspended by the stem with the
fingers of one hand, whilst the bran is poured round it with the other;
the jar being occasionally gently shaken as the process of packing
proceeds. Some paper is then laid over the top of the jar, the mouth or
cover of which is, lastly, tied firmly over with bladder, to exclude the
air and moisture. See FRUIT, &c.
=GRAPH'ITE.= See PLUMBAGO.
=GRATE.= A frame of iron bars used for burning coal as fuel. In the
construction of a grate it is desirable to make the perpendicular height
of the fuel as great as is consistent with safety. A stratum of burning
coal will radiate considerably more heat into an apartment if placed
vertically than if arranged horizontally; besides which a great saving of
fuel will be effected in proportion to the heat radiated. Hence the faulty
construction of the old-fashioned wide grates. The fuel should also be so
divided in a fireplace as to be easy of ignition, and so placed as to give
free access of air to all its parts, as the smoke is then more likely to
be burnt.
=GRAV'EL.= A collection of small pebbles commonly mixed with sand or clay,
or both. Gravel for garden walks is chosen for its fine colour and binding
properties. The gravel of Kensington and Wimbledon is esteemed the finest
in the world. Gravel walks when once in order, may be rendered nearly
equal to asphalt by pouring over them tar or a mixture of tar and pitch,
absorption being promoted, if required, by the application of a hot iron.
=Gravel.= In _pathology_, a term popularly applied to calculous matter
formed in the kidneys, and passing off in the urine; and sometimes to
distinct calculi or concretions in the bladder itself.
An attack of gravel, as commonly understood, is accompanied by a deposit
of red, gritty, sand-like particles in the urine, which do not dissolve
when the urine is heated. The deposit consists of uric acid. Pains in the
loins are a common accompaniment of gravel, and there is also sometimes
pain in passing water.
_Treat._ Give twenty minims of solution of potash (of the B. P.) three
times a day in barley water; or twenty grains of bicarbonate of soda, also
three times a day. If the attack be attended with much pain a brisk dose
of Gregory's powder should be additionally taken every morning. Vichy
Water will also be found a useful remedy. See CALCULUS.
=GRAVIM'ETER.= See HYDROMETER.
=GRAV'ITY.= _Syn._ GRAVITATION. The attractive force by which bodies fall
towards the centre of the earth. Weight is the measure of gravity. The
determination of the relative weight of bodies with reference to a given
standard, is explained under SPECIFIC GRAVITY.
=GRA'VY.= The juice or liquid matter that drains from dressed meat after
it is placed on the dish for serving. The common practice among cooks is
to pour a spoonful or two of boiling water or broth over the joint, to
increase the quantity. The natural gravy that oozes from the meat after it
is cut is the richest and most wholesome. Made gravies are prepared by
adding spice and flavouring to the foregoing, or to strong meat soup.
The gravy for roast meat is usually made by sprinkling a little salt on
the joint after it is placed in the dish, and then pouring some boiling
water over it; this washes off some of the brown, and makes a coloured
liquid in the dish.
Another method for making gravy for roast meat is the following:--Take any
bones, scraps of cold meat, or trimmings of the joint, put them in a half
pint of water, with a little salt and half an onion, let them stew all the
time the meat is roasting; colour with a little burnt sugar. When the meat
is done, pour the dripping from it carefully into a basin, leaving the
gravy at the bottom of the tin; strain the gravy you have made into this,
let it boil, and pour round (not over) the meat. If the gravy is liked
thick, put a dessert-spoonful of flour, mixed into a smooth paste, with
two of cold water, into the saucepan five minutes before you strain it.
See SAUCE.
=GRAY.= _Syn._ GREY; GRIS, Fr. A mixture of black and white. Delicate
grays result from mixture of the three elementary colours, red, yellow,
and blue, in which the blue preponderates to a greater or less extent.
=GRAY DYE.= _Syn._ TEINTE GRISE. Gray is dyed with the same materials as
black, but both the bath and mordaunt are used in a more diluted state.
COTTON goods may be worked in sumach and then in copperas; this gives
rather a bluish grey, which may be modified to any particular hue by the
addition of suitable colouring matter. To make it yellowish, a small
amount of fustic and alum are employed; to make it 'fuller,' peachwood and
Lima-wood with alum are used. The methods of obtaining grey on SILK and
WOOL are very numerous; they are similar in principle to the above, all
depending on the blending of the three primary colours, or on the
modification of weak blacks. See BLACK DYE.
=GREASE.= A general term applied to soft animal fats; as BEAR'S GREASE,
GOOSE GREASE, &c.
=Grease.= An inflammatory affection of the heels of horses, which produces
dryness, scurfiness and stiffness. The _treatment_ consists of emollient
poultices, accompanied with physic and diuretic balls, to subdue the
inflammation, followed by mild astringent lotions or ointments.
=GREAVES.= _Syn._ GRAVES. The sediment of melted tallow, consisting
chiefly of animal membranes mixed with fat, made up into cakes. Used as a
coarse food for dogs.
=GRE'CIAN WATER.= See HAIR DYES.
=GREEN.= _Syn._ VIRIDIS, L.; VERT, Fr. Of the colour of the leaves of
growing plants; _subst._ a green colour.
=GREEN DYE.= _Syn._ TEINTE VERTE, Fr. All the green dyes in use, with the
practically unimportant exception of Chinese green and oxide of chromium
green, are compounded of blue and yellow. The goods, in practice, are
generally dyed blue first, observing to regulate the shade according to
that of the intended green; they are then dried, rinsed, and passed
through a yellow bath, with the like precautions, until the proper shade
is obtained. See BLUE DYE, YELLOW DYE, &c.
=GREEN PIG'MENTS.= Several of the green pigments of commerce are obtained
from copper. Oxide of chromium furnishes some which are very beautiful.
Many are formed by the mere mechanical admixture of blue and yellow
pigments. The bright blues and yellows, when mixed in this way, produce
the liveliest greens; orange, or red and blue, and the yellowish browns
and blue, the more dingy greens. In this way are produced all the
extemporaneous greens of the artist. Nickel and titanium also furnish
green colours, but these are not in common use. The following list
embraces all the best-known and most useful green pigments:--
=Green Arsen'ical.= Arsenite and aceto-arsenite of copper. See GREEN,
SCHEELE'S and SCHWEINFURT (_below_).
=Green, Barth's.= From yellow lake, Prussian blue, and clay, ground
together.
=Green, Bice.= Same as mountain green.
=Green, Bremen.= This is properly green verditer, but other preparations
are frequently sold under the name.
=Green, Brighton.= A mixture of impure acetate of copper and chalk,
prepared as follows:--
To sulphate of copper, 7 lbs., add sugar of lead, 3 lbs.; each separately
dissolved in water, 5 pints; mix the solutions, stir in of whiting, 24
lbs., set the resulting paste on chalk stones, and when dry grind it to
powder.
=Green, Brunswick.= This is probably a crude chloride of copper, but a
mixture of carbonate of copper and alumina or chalk is now commonly sold
under the name in the shops.
_Prep._ 1. A saturated solution of sal ammoniac, 3 parts, is poured over
copper filings or shreds, 2 parts, contained in a vessel capable of being
closed up, and the mixture is kept in a warm place for some weeks, when
the newly formed green pigment is separated from the unoxidised copper, by
washing the mixture on a sieve; it is then edulcorated with water, and
slowly dried in the shade. Colour very deep and rich. The lighter shades
are produced by the addition of sulphate of baryta.
2. A solution of crude carbonate of ammonia or bone spirit is added to a
mixed solution of alum and blue vitriol, as long as it affects the liquor;
in a short time the precipitate is collected, washed and dried. The
various shades of green are produced by using different quantities of
alum, which pales and cheapens it.
=Green, Chrome.= The superb green pigment used by enamellers under this
name is the green oxide or sesquioxide of chromium. A hydrated oxide of
chromium forms the emerald green of Pannetier; it is prepared by melting
in a crucible equivalent quantities of anhydrous boracic acid and
bichromate of potassium, and treating the fused mass with water. The
hydrated oxide thus produced is washed and finely triturated.
The chrome green of the oil and colour shops is a mixture of chrome yellow
and Prussian green.
=Green, Cop'per.= Green bice or mountain green, Brunswick green, emerald
green, verditer, and several other well-known pigments, may be thus named.
=Green, Em'erald.= This term is commonly applied to the aceto-arsenite of
copper, as prepared in England. It is the same compound, chemically
speaking, as Schweinfurt green (which _see_).
_Prep._ A pulp is formed with verdigris, 1 part, and boiling water q. s.,
and after being passed through a sieve, to remove lumps, is added
gradually to a boiling solution of arsenious acid, 1 part, in water, 10
parts, the mixture being constantly stirred until the precipitate becomes
a heavy, granular powder, when it is collected on a calico filter, and
dried on chalk stones.
=Green, Frise.= _Syn._ FRIEZLAND GREEN. This resembles Brunswick green.
=Green, Gellart's.= A mixture of cobalt blue and flowers of zinc with some
yellow pigment.
=Green, Impe'rial.= Schweinfurt green (see _below_).
=Green, Iris.= A pigment prepared by grinding the juice of the petals of
the blue flag with quicklime. It is very fugitive.
=Green Lake.= See LAKE.
=Green, Min'eral.= This is the same as mountain green.
=Green, Mitis.= Another of the many synonyms of Schweinfurt green.
=Green, Mountain.= This pigment is properly the native green carbonate or
bicarbonate of copper (malachite) ground to powder, either with or without
the addition of a little orpiment or chrome yellow. That of the shops is
commonly prepared by adding a solution of carbonate of soda, or of
potassa, to a hot mixed solution of sulphate of copper and alum. Green
verditer is commonly sold for this article. According to Watts, mountain
green is the same as Neuwieder green.
=Green, Neuwieder.= Schweinfurt green mixed with gypsum or sulphate of
baryta.
=Green, Prussian.= The sediment of the process of making Prussian blue
from bullock's blood or horns, before it has had the hydrochloric acid
added to it. It is also prepared by pouring liquid chloride upon freshly
precipitated Prussian blue. As now sold, this pigment is generally a
mixture of Prussian blue and gamboge.
=Green, Rinman's.= This resembles that of Gellert.
=Green, Sap.= A very fugitive pigment, prepared from the juice of
buckthorn berries. The berries are allowed to ferment for a week or eight
days in a wooden tub. The juice is then pressed out, strained, a little
alum added, and the whole evaporated to a proper consistence; it is next
run into pigs' bladders, and hung up in a dry situation to harden. An
inferior article is made from the juice of black alder, and of evergreen
privet. It is a common practice to add 3/4 pint of lime water and 1/2 oz.
of gum Arabic to every pint of either of the above juices.
=Green, Scheele's.= This is arsenite of copper.
_Prep._ 1. White arsenic (in powder), 1 part; commercial potash, 2 parts;
boiling water, 35 parts; dissolve, filter, and add the solution gradually,
whilst still warm, to a filtered solution of sulphate of copper (cryst.),
2 parts, as long as a precipitate falls; lastly, wash the newly formed
pigment with warm water, and dry it.
2. (Ure.) Powdered arsenious acid, 11 oz.; carbonate of potassa, 1-1/2
lb.; boiling water, 1 gall.; dissolve, filter, and add the solution, as
before, to another solution of crystallised sulphate of copper, 2 lbs., in
water, 3 galls. _Prod._ 1-1/2 lb. A very fine grass-green colour.
=Green, Schweinfurt.= This splendid green pigment is the aceto-arsenite of
copper.
_Prep._ 1. Acetate of copper and arsenious acid, equal parts, are each
dissolved separately in the least possible quantity of boiling water, and
the solutions mixed whilst still as hot as possible; an olive-green
precipitate falls, which, by being boiled in the liquor 5 or 6 minutes,
changes to a dense granular powder of a superb green colour.
2. Instead of boiling the solution containing the precipitate, it is
allowed to cool and stand for several hours, or until the powder assumes a
granular and beautiful tint. Very rich.
3. (Kastner.) Arsenious acid, 8 lbs., is dissolved in water as before, and
added to verdigris, 9 or 10 lbs., diffused through water q. s., at 120°
Fahr., the pap of the other being first passed through a sieve; the mixed
ingredients are then set aside till the mutual reaction produces the
proper shade.
4. (Dr Ure.) Sulphate of copper, 50 lbs., and lime, 10 lbs., are dissolved
in good vinegar, 20 galls., and a boiling hot solution of white arsenic,
50 lbs., is conveyed as quickly as possible into the liquor; the mixture
is stirred several times, and then allowed to subside, after which it is
collected on a filter, dried and powdered. The supernatant liquor is
employed the next time for dissolving the arsenic.