A Treatise on Calico Printing, Metallic Substances.

A Treatise on Calico Printing, VOL. I-II
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1792These consist chiefly of a verifiable earth combined with phlogiston, and are therein fusible; they are likewise ponderous, opaque, and sparkling: a third prinqiple is contended for by some chymists, called mercurial earth, but it is doubted to exist by others.

Metallic substances readily unite with most acids, and in that case an ebullition with vapours arise; by degrees the metallic particles become invisible in their solvents, and the metal is then said to be dissolved; but, as with alkalies, an acid can only take up such a portion as is sufficient to destroy some of its properties, and to render others weaker. The affinity that metallic substances have with acids, is less than what they have with absorbent earths and fixed alkalies, so that the acid which will unite with these substances, will decompound the metalline salts, and precipitate the metal, which are then called precipitates and magesteries.

Metallic substances are 6 in number, 2 perfect viz. Gold (Sol) Silver (Luna) and 4 imperfect, viz. Copper (Venus) Iron (Mars) Tin (Jupiter) and Lead (Saturn;) Quicksilver (Mercury) is by some, called a seventh metal.


Gold.

As metals are the heaviest substances known, gold is the heaviest of all, and when pure, is unalterable in fire as far as any experiment hath hitherto proved, neither can it be dissolved by any pure acid; but only by the acid of nitre mixed with that of sea-salt, called aqua regia. Gold is likewise the most ductile and most malleable of all metals.

A remarkable circumstance, and as yet not clearly accounted for, is the fulminating quality of the precipitate by an alkali or absorbent earth, gently dried and exposed to a certain degree of heat; this is called aurum fulminans, but the acid of vitriol poured on it, will deprive it of that quality, as will likewise be the case, if it be cleared of its saline particles, which, washing it in water will accomplish.

Gold is not affected by a pure sulphur when combined with an alkali.


Silver.

This metal is the next perfect to gold, being lighter and less ductile, but like gold it resists the greatest force of fire, in which is their superiority over all metals: The true solvent of silver is the nitrous acid, the chrystals formed thereby are particularly caustic; it is likewise soluble by the vitriolic acid, if it be concentrated, but spirit of salt, and aqua regia, as well as the; other acids, are not capable of affecting it: yet in reality it has a greater affinity with both, than, with the vitriolic; for if the vitriolic or marine acid be added to a solution of silver in the nitrous, the silver will directly join it, and the precipitate procured by the marine acid, is called Luna Cornea: Fixed alkalies and absorbent earths will separate the silver from the nitrous acid, though the nitrous acid cannot act on it when mixed with an equal quantity of gold, but when in a triple proportion it can with ease: If aqua regia be employed when they are in equal quantities the separation will be effected, by the gold being dissolved and the silver left free; but the operation by aqua fortis is to be preserred, it having no effect on gold, and a little of the silver is always taken up by the aqua regia: Silver united with sulphur soon flows, and forms a mallable mass, the colour of lead: — Solution of silver in the nitrous acid stains hair, bones, wood, &c. from a brown to a black, and gives a stain to marble and other stones.


Copper.

This is the first of the imperfect metals, it resists fire a long time, unites readily with gold and silver, and is soluble in all the acids, neutral salts, and even in water; to some imparting a green colour, and to others a blue: dissolved in vitriolic acid it forms blue crystals, called blue vitriol or vitriol of copper: dissolved in aqua regia, the marine or nitrous acid, it forms a salt which does not crystalize, and runs in the air: The precipitates by alkalies or earths retain nearly the colour the solution gives: mingled with nitre and exposed to the fire, as well as the other imperfect and semi-metals, it is sooner decomposed and calcined than if presented alone: mixed with sulphur and made red hot, it soon melts and forms a new compound more fusible than alone.


Iron.

This metal stands alone for its property of being attracted by the magnet, but loses it if reduced to a calx, or converted to an earth: by repeated melting it is rendered purer than by havingonly undergone fusion, but is not malleable till after being heated red and hammered in all directions: before this process it is called pig-iron but bar-iron afterwards; and is then harder to fuse: Fusing it with articles that contain phlogiston, or enclosing it in phlogiston matters, and. exposing it thus in just a red hot state for a. certain time, it is converted into steel or hardened: Suddenly quenching it when red-hot in a cold liquor, the hardness is augmented, and that in proportion to the heat of the metal and coldness of the water; it may be brought back by cementing it with calcined bones, chalk, &c. rendering it red hot and leaving it to cool gradually, or if heated alone, and left thus to cool, the temper given to steel is destroyed. Iron being calcined turns to a yellowish crust, by losing its phlogiston, and is then called crocus martis or saffron of mars. All acids, as well as certain salts, alkalies, and water itself, operate on it, but the vitriolic acid dissolves it the readiest, rendering the solution of a beautiful green; the crystals produced by which are called green vitriol, vitriol of mars, or copperas: Ochre is, the sediment produced from green vitriol dissolved in water: Spirit of nitre dissolves iron with, ease, producing a brownish yellow, but the calx formed by this solution cannot be a second time dissolved, for having lost its phlogiston, the nitre will not act on it, neither does this nitrous solution crystallize: The solution by spirit of salt is green, the vapours of which are inflammable, as well as those caused by the vitriolic acid: the solution in aqua regia is yellow.

Iron having a greater affinity with spirits of nitre and spirits of vitriol, than either silver or copper has, if offered to a solution of either, the silver or copper will precipitate, by the acid quitting them and joining the iron: Iron filings exposed to the dew, turn entirely to a ruft, called crocus martis apeciens: united with sulphur, it acquires a great degree of susibility: Iron makes a part of almost all substances (which the magnet will discover) it is found in the caput mortuum of all vegetable substances, even in honey, the earth being supposed to be impreg nated with a ferruginous or vitriolic matter, and from thence received into vegetables, and from vegetables it passes into animals: It is the only metal that sparkles in the focus of a burning glass.


Tin.

This is the lightest of all metals, has but little ductility and runs long before it is red hot: The calx when vitrified, being mixed with some other substance is called enamel, which is differently coloured by means of other metalline calces: tin unites with all metals, but destroys their ductility and malleableness, lead excepted: Those the most ductile it effects the soonest, and in the greatest degree: Bronze and bell-metal are made from a composition of this metal with zinc: mixed with lead it produces pewter, and is used quick-silver in making looking-glasses.

The vitriolic, nitrous and marine acids have an affinity with it, but cannot easily dissolve it, as they only reduce it to a kind of calx: The proper solvent (as mentioned more fully further on) is aqua regia, and has even a greater affinity with it than with gold; Gold precipitated by this method is a most beautiful colour, and used as a red for porcelain and enamelling: It has the property of giving red colours in general, hence tin vessels are used in making fine syrup of violet. It is not affected by water as iron and copper are, but it loses its polish om exposure to the air: It readily unites with sulphur.


Lead.

This is the heaviest of all metals, gold and silver excepted, is softer than any, and except tin, melts the easiest: Vitriolic acid affects it nearly as it does silver; the nitrous acid dissolves it with much ease, and in great quantities; the crystals are of a sweet taste, of a yellqwim colour, and are not easily dissolved in water: Spirit of salt, or the salt in substance, added to the solution in nitrous acid, produces a white precipitate called plumbum cornea, which dissolves easily in water: Being melted, it hardens into a kind of horny substance, like the luna cornea (whence the name:) Lead boiled a long time in a lixivium of fixed alkali will partially dissolve: It is rendered very refractory by sulphur.


Quicksilver.

This substance is soluble in acids, but to each acid, particular circumstances are annexed; thus the vitriolic acid concentrated, and made boiling, hot, reduces it apparently to a white powder; which on the affusion of water turns yellow and is called turbith mineral.

Quicksilver is easily dissolved by the nitrous acid; the solution is clear, and as it cools. shoots into crystals: If evaporated to dryness, it pro duces red precipitate: With solution of copper the precipitate is green.

Combined with marine acid, it farms a metalline salt, the crystals of which, called corrosive sublimate, are pointed like daggers, and is the most violent corrosive hitherto discovered: from this sublimate is produced yellow precipitate: Quicksilver unites with sulphur very easily, and produces by the mere mixture, ethiops mineral: By rendering the union more perfect by a strong heat, a ponderous substance is procured called cinnabar, which finely ground produces vermillion.