Chapter IX: Preface: ─────── (9)

In the state of the Connecticut, North America, it is said that antimony, in a pure metallic form, is found in such abundance that, in some places, large masses of it may be seen lying on the surface of the ground. The principal supply of antimony in Europe is from an ore which is found in Hungary and Norway, called _sulphuret of antimony_. The process of bringing it into a state for use is very simple. The mineral is put into pots, each of which has a hole in the bottom, and which is placed on another pot bedded in the earth. The upper pots, which are filled with the mineral, are heated. As soon as the antimony is fused it flows into the lower pots, while the substances with which it was combined remain in the upper ones. The antimony fixes, and forms cakes of the shape of the pots which receive it. In this state the metal presents, in its fracture, a surface thick─set, with long needle─shaped crystals, which, lying by the side of each other, compose, as it were, the whole of the mass. It is afterwards re─melted and cast into cakes for sale.

This metal, in a pure state, or alloyed only with a very small portion of silver and iron, is found in veins of mountains in some parts of France and Sweden, occurring in massive and kidney─shaped lumps of white colour.

The only mine of antimony in Britain, which is of any importance, is at Glendinning in Dumfries─shire. It was discovered in 1760, in searching for lead ore, but was not regularly worked till 1763. In the first five years about a hundred tons’ weight of antimony were obtained from it. This at 84_l._ per ton, produced the sum of 8400_l._ The undertaking was afterwards relinquished, but, as the price of antimony is now at least thrice what it then was, it is supposed that this work, if resumed, might prove an advantageous speculation. The vein of ore is only from eight inches to a foot and a half in thickness.

Antimony was known to the ancients. The earliest account we have of it is in the Sacred Writings. The passage in the Second Book of Kings,[4] which states that, on the approach of Jehu to the city of Jezreel, “Jezebel painted her face,” implies, in the original, that she stained her eyes and eyebrows with antimony, for the purpose of making them look black and large, a custom which, at that period, was prevalent in several of the Eastern countries. Antimony was likewise considered by the ancients a remedy against inflammations of the eyes.

This metal is the basis of many of the officinal preparations which are now in use; and it was the basis of many others which were formerly used, but are now discontinued. No mineral substance has so much attracted the attention, or so much divided the opinion of physicians, as antimony. One party extolled it as an infallible specific for almost every disease; whilst another described it as a virulent poison, which ought to be expunged from the list of medicines. It was on this metal that the alchemists of the middle ages principally founded their hope of discovering the philosopher’s stone; and, by a kind of good fortune, of which we can cite but few examples, it has happened that, in pursuing a chimera, they hit upon a succession of important realities. To the unremitted perseverance with which they tormented this metal, if we may so express it, the art of healing has been most essentially indebted.

Footnote 4:

Ch. ix. v. 30. See also Ezek. Ch. xxiii. v. 40.

The first rational account of the properties of antimony was given, about the end of the seventeenth century, by a French chemist, whose name was Lemeri. Its great importance in medicine will be seen by an enumeration of some of the most valuable preparations of it which are still in use.

_Antimonial Wine_ is prepared from antimony, in conjunction with white Lisbon wine. It is employed as an emetic; but, if mixed with milk, this quality is said to be completely destroyed, and it becomes narcotic.

_Emetic Tartar_, which is much more employed in this country than all the other antimonial preparations put together, is formed from antimony mixed with its own weight of tartar, and a certain proportion of water, and afterwards boiled, filtered, and suffered to crystallize.

_Butter of Antimony_ is obtained from a combination of antimony with corrosive sublimate. It is denominated by chemists muriat of antimony, and is usually a thick fatty mass of greyish white colour.

_Glass of Antimony_ is a vitreous substance of reddish brown colour, which is occasionally used in medicine, but more frequently in colouring the imitations of yellow diamond, Oriental, Brazil, and Saxon topaz, hyacinth, emerald, and beryl.

_James’s Powder_, or _Antimonial Powder_, is a well─known medicine, composed of phosphat of lime and antimony.

An alloy consisting of sixteen parts of lead and one part of antimony constitutes the metal of which _printers’ types_ are formed. This alloy does not differ from lead except in being considerably harder and more tenacious. The plates on which music is engraved are formed of a mixture of tin and antimony; and the oxides of antimony are used for the colouring of glass.

246. _BISMUTH is a reddish white semi─metal, harder than silver, and composed of broad brilliant plates adhering together._

_It is nearly ten times heavier than water, and is so brittle as readily to break under the hammer. None of the semi─metals are so easy to be fused as this; it melts even in the flame of a wax candle, and long before it becomes red hot, and has the singular property of expanding as it cools._

The ores of bismuth chiefly occur in Sweden, Norway, Germany, France, and England. This metal appears to have been known to the ancients. It was confounded by them with tin; and, even in our own manufactories, it is known to the workmen by the name of _tin─glass_.

It is not of much use in the arts; but its fusibility renders the working of it very simple and easy. It is employed in the composition of some of the soft kinds of solder; and is also used for giving hardness to tin and other metals. Amalgamated with mercury it renders that metal less fluid; and the addition of it to mercury and tin is found useful in the foliating or silvering of looking─glasses. Some manufacturers use it in the composition of pewter; but it is said that this ought not to be done, particularly for the formation of vessels intended to contain food, as bismuth partakes of the noxious properties of lead, and sometimes contains even arsenic. It is also occasionally employed in the fabrication of printers’ types.

A very singular metal is formed by melting together eight parts of bismuth, five of lead, and three of tin. Tea─spoons formed of this metal surprise all who are unacquainted with their nature: they have somewhat the appearance of common spoons, but they melt as soon as they are put into boiling water.

Bismuth reduced to powder, mixed with the white of eggs and applied to wood, gives it, when gradually dried and rubbed with a polisher, the appearance of being silvered. If this metal be dissolved in aquafortis (30), and water be poured into the solution, a white powder precipitates, which is an oxide of bismuth, and which, after being well washed, is used as a pigment, under the name of _pearl─white_. From its beautiful appearance, this powder is sometimes employed by ladies for painting their skin; a practice which cannot be too much condemned, both on account of the danger with which it is attended, and from its soon injuring both the texture and natural colour of the skin. It has the further disadvantage of turning black when touched by the fumes of fetid and other substances; and ladies, who have used this cosmetic, and have afterwards bathed in the Harrowgate waters, have come from the bath a perfectly tawny colour. It was probably the oxide of bismuth which the Roman ladies used for whitening their skin; for Martial, in speaking of a lady, who made too free an use of cosmetics, describes her as afraid even of the sun. The oxide of bismuth is used in the composition of most of the pomades employed in France for painting the face.

A preparation of bismuth has lately been employed in medicine, as a remedy against spasmodic affections of the stomach.

The following is a pleasing experiment, illustrative of metallic crystallization. Melt a ladleful of bismuth, and allow it to cool slowly and quietly till a thin crust is formed on the surface: then, with a pointed iron, make two small opposite apertures through the crust: and, through one of these, quickly pour out the fluid portion, as carefully and with as little motion of the mass as possible. The air having entered by the other aperture, there will appear, on removing the upper crust by means of a chisel, when the vessel has become cold, a cup─shaped concavity, studded with very brilliant crystals, and more or less regular according to the quantity of metal employed, the tranquillity and slowness with which it has cooled, and the dexterity with which the fluid portion of the mass was poured off before it became solid. The same effect may be produced by melting bismuth in a crucible which has a hole in the bottom, lightly closed by an iron rod or stopper; this is to be drawn out when the mass begins to congeal. By so doing, the upper portion, which is fluid, is made to run off, and a cake studded with crystals will be left.

247. _COBALT is a semi─metal of grey colour with a shade of red, brittle, somewhat harder than silver, nearly eight times as heavy as water, is attracted by the magnet, and is itself capable of being rendered permanently magnetical._

_The ores of cobalt are not numerous, and are, for the most part, combinations of this substance with other metals, or of its oxides (24) with arsenic, or with sulphuric acid (21)._

The name of this metal implies an evil being, (_Kobold_, German, goblin) and is said to have been given on account of the vapour of arsenic, which issues from it, tormenting the miners, and making them believe that they are afflicted by wicked spirits. Hence it was once customary in Germany to introduce into the church service a prayer that God would preserve miners and their works from _cobalts_ and _spirits_.

Cobalt is found in several parts of Europe, but most plentifully in the southern borders of France, and in Saxony; and the cobalt ores of Hesse, although they were formerly used for no other purpose than the mending of roads, are said now to yield a clear profit of nearly 15,000_l._ a year. Some parts of our own country yield this substance in considerable abundance, particularly the Mendip Hills in Somersetshire, and a mine near Penzance in Cornwall.

After the ore is taken from the earth, it is broken into pieces about the size of a hen’s egg, and the stony parts are picked out. The sorted mineral is then pounded in mills, and sifted through brass─wire sieves. The lighter particles are next carried off by water. After undergoing some other preparations, to rid it of the impurities and foreign matters with which it is connected, it appears in the form of a dark grey oxide. The working of the cobalt ores in Germany is considered so injurious, on account of the arsenic with which they are combined, that much of the labour is performed by criminals who are condemned to it for the commission of crimes which, by the laws of the country, have deserved the punishment of death.

As a metal, cobalt was unknown till the year 1733, when it was discovered by a celebrated Swedish chemist whose name was Brant. In its metallic state it is not employed in the useful arts; but in a state of oxide it is found extremely valuable in the colouring of porcelain, in painting, enamelling, and for other purposes. Cobalt and ultramarine form the most permanent blue colours with which we are acquainted. The old painters generally used them for the representation of the sky and of blue drapery, and this is the reason why these parts in some old pictures have been found so much more durable than any others.

_Zaffre_ is an oxide of cobalt mixed with about three times its own weight of calcined and pounded flint. It has been chiefly imported into this country from Saxony and Bohemia, but it is now also manufactured from cobalt dug from mines in the Mendip Hills and in Cornwall. In Staffordshire there are several persons who carry on a considerable trade in preparing this colour for the earthenware manufacturers of that county.

This substance is extremely valuable for the colouring of porcelain and glass; as it resists without change, the effects of the most intense heat. Hence also it is advantageously used for giving various shades of blue to enamels, and to glass manufactured in imitation of lapis lazuli, turquoise, sapphire, and various precious stones. So intense is the colour imparted by it that a single grain of zaffre will give a full blue tint to 240 grains of glass.

_Smalt_ is a kind of glass, of dark blue colour, formed by melting zaffre with three parts of sand and one of potash; when this substance is ground to a coarse powder, it has the name of _strewing─smalt_, and is much used by sign painters, as an ornamental filling up of the vacant space betwixt the letters of signs. In Germany it is frequently employed instead of sand for the purpose of drying ink after writing. The same substance reduced to a perfectly fine or impalpable powder, is the article which is sold under the name of _powder─blue_, and which is not only used by laundresses and others in the getting up of linen, but also as the basis of several kinds of paint; and by the manufacturers of writing and printing papers, to give a blue tinge to those articles.

A solution of the oxide of cobalt in spirit of salt (muriatic acid, 29) and afterwards diluted till nearly the whole of its colour disappears, forms one of the most beautiful _sympathetic inks_ with which we are acquainted. If a landscape be drawn with Indian ink, and, afterwards, the foliage be washed over with this solution, it will have no peculiar appearance; but, on holding the paper near the fire, the part representing the vegetation will gradually assume a green tint, which will subside on removing the paper into a cool situation.

248. _MANGANESE, in the state that we usually see it, is a black oxide of a metal which is of a silvery grey colour, of leafy or foliated texture, and somewhat more than six times as heavy as water._

Mines of manganese have long been worked in several parts of Great Britain, but particularly in the counties of Devon and Somerset. Near Exeter and in the Mendip Hills this mineral is found in great abundance.

It is employed for various useful purposes. In the manufacture of the finer kinds of glass it is used in a double capacity, both as a colouring material and as a destroyer of colour. As a colouring ingredient, the imitators of several precious stones are indebted to it for the red and purple tints which they give to the oriental ruby, the balais ruby, and the amethyst.

The violet colour given to porcelain is obtained from manganese. This substance is also used for the glazing of black earthen ware, as a paint, and an ingredient in printers’ ink. As a discharger of colour it is applied in small quantities, and, by the oxygen which it gives out, it is said completely to destroy any tinge left in the glass, by the presence of iron, and some other colouring matters. This property has obtained for it the appellation of the _soap of glass_.

It is from manganese that all the oxygen gas (21) used by chemists is obtained. By the application of a red heat this is yielded in such abundance that an ounce of the oxide of this metal will yield about two quarts of gas. The consumption of manganese has, of late years, become very considerable by the discovery of the oxygenated muriatic acid, which is now extensively used in the bleaching of linen and cotton; that liquor being made by the distillation of the oxide of manganese with spirit of salt (muriatic acid, 29).

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COMPOUND MINERALS,

OR

ROCKS.

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249. There exist considerable masses of minerals in a state of combination, or aggregation with each other. These constitute the rocks and soil of which the globe of the earth is composed; and the study of them is called GEOLOGY. The opinions of learned men relative to their structure, and original formation, have produced various systems denominated _theories of the earth_; but, when we consider that the greatest depth beneath the surface to which the art and industry of man have been able to penetrate, does not exceed 1/35000 part of the earth’s diameter, we must confess that this is very insufficient to allow of any correct opinion being thereby formed concerning the structure of the whole.

Modern geologists, for the more convenient arrangement of the compound minerals, have divided them into four classes, which they denominate _primitive rocks_, _secondary rocks_, _alluvial depositions_, and _volcanic rocks_.