Chapter IV: Preface: ─────── (4)

Thin plates of mica are adopted, in many parts of Siberia and Muscovy, to supply the place of glass for windows. In the shipping of Russia it is considered preferable to glass, as the concussion produced by the firing of the guns does not shatter it. It is employed instead of window glass in Peru and New Spain; and also in Pennsylvania. Mica may be advantageously substituted for horn in lanterns, as it is not only more transparent, but is not susceptible of injury from the flame of the candle. It has, however, the inconvenience of soon becoming dirty; and of having its transparency destroyed by long exposure to the air. Mica is used for enclosing objects that are intended to be viewed by microscopes.

So plentiful is this substance in Bengal, that, for the value of five shillings, as much of it may be purchased as will yield a dozen panes, each measuring about twelve inches in length and nine in breadth, and so clear as to allow of ordinary objects being seen through them at the distance of twenty or thirty yards.

Mica, when powdered, is sold by stationers on the Continent, in place of sand, for absorbing ink in writing, but it does not dry sufficiently quick to be of much use in this respect. In Russia it is employed in different kinds of inlaid work. It is sometimes powdered, and intermixed with the glaze in particular kinds of earthen ware. The heat which melts the glaze has no effect on the mica: hence it appears, dispersed throughout the glaze, like plates or scales of silver or gold. Some artists use it in making artificial avanturines (85).

It must be observed that the best mica is of a pure pearl colour; and, when split into leaves, presents a smooth surface.

SOAPSTONE FAMILY.

124. _STEATITE, or SOAPSTONE, is a soft and unctuous substance, which has much the appearance of soap; and is generally of a white or grey colour, intermixed with greenish or yellowish shades._

_It is somewhat more than twice as heavy as water; and is distinguished from indurated talc (135) by not splitting, like that substance, into slaty fragments._

In the counties of Devon and Cornwall, and the islands in the vicinity of the Lizard Point, this mineral is found in considerable abundance. It possesses many of the same properties as fullers’ earth, and is, like that substance, employed in the scouring of woollen cloths. When mixed with water it may be formed into a paste; and, in this state, it is easily worked, like clay, for the manufacture of earthen ware. In the porcelain manufactory at Worcester considerable quantities of steatite are employed. According to Dr. Shaw, the Arabs use it in their baths, instead of soap, to soften the skin.

As it becomes hard in the fire, and does not alter its shape, this substance has been successfully adopted for imitations of engraved gems. The subjects are engraved upon it with great ease in its natural state; it is then exposed to a strong heat; afterwards polished, and then coloured by means of certain metallic solutions.

We are informed by travellers, that some of the savage tribes eat steatite, either alone, or mixed with their food, to deceive hunger. The inhabitants of New Caledonia eat considerable quantities of it. Humboldt, the South American traveller, assures us that the Otomacks, a savage race of people, who live on the banks of the Orinoco, are almost wholly supported, during three months of the year, by eating species of steatite, or potter’s clay, which they first slightly bake, and then moisten with water. M. Golberry says that the negroes near the mouth of the Senegal mix their rice with a white kind of steatite, and eat it without inconvenience.

In some parts of Spain a variety of steatite is found, which is used by artists under the name of Spanish chalk. When slightly burned, this mineral is sometimes used as the basis of rouge.

125. FIGURE STONE _is a kind of steatite, which has, internally, a glimmering and resinous lustre, and a slaty or splintery fracture_.

From its softness, and yet solidity of texture, this mineral can easily be fashioned into various shapes, even with a knife. Hence in China, where it frequently occurs, it is cut into grotesque figures of various kinds, which the French call _magots de la Chine_, into cups, vases, pagodas, snuff─boxes, and other articles.

126. _MEERSCHAUM, or SEA─FROTH, is a singular kind of mineral, of yellowish or greyish white colour, sometimes so light as to float in water: when fresh dug it has nearly the consistence of wax._

_If exposed to a strong heat, it becomes so hard as to yield sparks with steel._

The principal use to which meerschaum is applied is in the formation of the bowls or heads of tobacco─pipes used by the Turks, and the quantity consumed for this purpose is very great. It is found in a fissure of grey, calcareous earth, about six feet wide, near Konie, in Natolia, where upwards of six hundred men are employed in the digging and preparation of it; and the sale of it supports a monastery of dervises established at that place. The workmen assert that it grows again in the fissure, and puffs itself up like froth. It is prepared for use by being first agitated with water in great reservoirs, then allowed to remain at rest for some time. The mixture soon passes into a kind of fermentation, and a disagreeable odour, resembling that of rotten eggs, is exhaled. As soon as this smell ceases, the mass is further diluted with water, which, after a while, is poured off. Fresh water is repeatedly added, until the mass is sufficiently washed and purified. The meerschaum, in this state, is dried to a certain degree. It is then pressed into a brass mould, and, some days afterwards, is hollowed out so as to form the head of the pipe. It is subsequently dried in the shade, and lastly is baked. In this state the pipe heads are brought to Constantinople, where they are subjected to further processes. They are first bailed in milk, and next in linseed oil and wax; and, when perfectly cool, are polished with rushes and leather. The boiling in oil and wax renders them capable of receiving a higher polish than could otherwise be given. When thus impregnated, they also acquire, by use, various shades of red and brown, which are thought to add considerably to their beauty. In Turkey, and even in Germany, meerschaum pipes that have been much used are more valued than those newly made, and this solely on account of the colouring they possess. Indeed there are people in those countries whose only employment consists in smoking tobacco pipes, until they acquire the favourite tints of colour. By long use, the heads become black: but if boiled in milk and soap, they are soon rendered white again.

It is asserted that the Turks spread meerschaum on bread, and eat it as a medicine; and that they cover with it the heads and eyes of dead bodies, previously to interment. As it lathers with water like soap, it is used by the Turkish women for washing their hair; and, as it absorbs oily matters, it is occasionally used, as fuller’s earth is with us, for the cleansing and scouring of cloth.

We are informed by Pliny, that a kind of bricks were made by the ancients, so light that, when dried, they would float in water. He describes them to have been formed of a spongy kind of earth, and to have had some resemblance to pumice stone, which he says might perhaps be applied to the same purposes as these bricks, if it could be obtained and wrought in sufficient quantity. Bricks of similar description have lately been made of a mineral substance found near Sienna, in Italy, and which is supposed to be meerschaum.

A kind of meerschaum has lately been discovered, in veins, in the serpentine (132) of Cornwall.

127. _BOLE is an earthy mineral, of yellowish or reddish brown colour, soft, and somewhat unctuous to the touch, and generally found in a massive state._

_It exhibits internally a glimmering lustre; and, when put into water, immediately absorbs it, and breaks down into small pieces with a crackling noise. This mineral is farther distinguished by its fracture being conchoidal, or appearing somewhat like the impression of a shell; and by its adhering strongly to the tongue._

Although bole is at present little used except as a basis of tooth powder, and a coarse kind of paint, it was formerly considered an important article in medicine, and used as an astringent. We are informed that tobacco pipes are sometimes made of this mineral; and that it is employed as an ingredient in the glaze of some kinds of earthen ware.

It is chiefly imported from the Levant; though it has also been found in considerable beds in Silesia and Saxony.

128. _LEMNIAN EARTH is a kind of bole of yellowish grey, or yellowish white colour, sometimes marbled with rust─like spots._

_It is distinguished from bole by being dry and not unctuous to the touch, dull internally, adhering slightly to the tongue, and its fracture being earthy._

With the ancients this mineral was considered an almost invaluable medicine. They procured it chiefly from Armenia, and the island of Lemnos, in the Grecian Archipelago. The Lemnian bole was held so sacred that it was dug in the presence of the priests of Venus, and, after having been mixed by them with goat’s blood, was moulded into cakes, which were impressed with the figure of a goat, to authenticate them. This done, it was administered as a consecrated remedy; and, even so lately as the sixteenth century, the vein of bole in Lemnos was annually opened on the sixth of August, and, after certain prayers by the priests, so much of the earth was taken out as was thought sufficient for the consumption of the ensuing year. The entrance was then closed, and the severest punishments were denounced against any one who should open it without permission. A portion of the earth was sent to Constantinople, where it was made into small cakes, and sealed by the ministers of the Emperor; the remainder was prepared in the island, and was impressed with the seal of the Governor. Not many years ago, it was customary with certain empirics on the Continent, to sell this substance in sealed packets, as a nostrum of great value, and particularly as possessing astringent properties of very extraordinary nature.

129. _FULLER’s EARTH is a well─known mineral, generally of greenish colour, more or less mixed with brown, grey, or yellow: of soft and almost friable texture, and somewhat unctuous to the touch._

_When put into water it immediately absorbs it, and breaks down into a fine pulp._

This earth is valuable for its property of taking grease out of woollen and other cloths, which, on a large scale, is effected by the operation called _fulling_, whence its name has been derived. This operation, which is performed by a kind of water mill, called a _fulling mill_, is particularly necessary with respect to new cloths, to extract from them the grease and oil that have been used in their preparation.

Fuller’s earth was formerly considered an article of such importance in England that its exportation was prohibited under severe penalties. It was then employed for most of those purposes for which soap has since been so extensively applied. In the dressing of cloth it is now so indispensable, that foreigners, although they can procure the wool, are never able, without fuller’s earth, to reach the perfection of the English cloths: and, in this country, incalculable quantities of it are consumed. As an article of domestic utility, it might be much more frequently used than it is, as a substitute for soap, in the cleaning and scouring of wooden floors and wainscots.

There are extensive beds of fuller’s earth in several of the counties of England. London is principally supplied from those of Kent, Sussex, and Surrey. At Wavedon, near Woburn, in Bedfordshire, a peculiarly fine kind is dug up from pits at the depth of ten or twelve feet below the surface of the ground; and no country in the world is known to produce fuller’s earth of quality so excellent as that obtained in England.

TALC FAMILY.

130. _JADE, or NEPHRITE, is a very hard and tough species of stone, of greenish or olive colour, somewhat unctuous to the touch, and looking as if it had imbibed oil._

_It is found massive, in blunt─edged or rounded pieces._

Nothing has so much tended to make this stone known, as a superstitious notion that a piece of it suspended to the neck will dissolve stones in the kidneys. Hence has been attained its appellation of nephrite, or divine stone; and hence have originated all those numerous amulets in the form of oval plates, hearts, fishes, birds, &c. pierced with holes for ribbons to pass through, which are seen in collections of the curious. Some of the Indian nations make talismans of jade.

From the roughness and tenacity of this stone, in addition to its hardness, it is very difficult to be cut and polished; and even the best polish which it is capable of taking as so imperfect, that a person ignorant of its nature might consider it to be merely smoothed and rubbed with oil. The ancient artists executed in it many beautiful and delicate figures; and it is impossible but to admire the industry and perseverance by which they produced even chains, and other hollow kinds of work, in jade.

The Turks cut it into handles for sabres and daggers, and into several kinds of vessels, to which they attach great value.

Jade occurs in granite (251) and gneiss (255) in Switzerland; but the most beautiful specimens of this mineral are brought from Persia, Egypt, and Siberia.

131. AXESTONE _is a kind of jade, but differs from it in having a slaty texture; and in being less transparent and less tough_. This stone is found in China, New Zealand, and on the banks of the river of Amazons, in America. And it is said that several of the tribes of American Indians form of it the axes which they use in place of iron. To explain how these people have been enabled to work a substance so rebellious as this is even to the file, and to other instruments of steel (of which they know not the use), it has been presumed that, when the stone is first taken from the earth, it is considerably less hard than when, by drying, its humidity is evaporated: that in this state they work it, and subsequently harden it, in some peculiar manner, by exposure to heat.

132. _SERPENTINE is a stone which, when polished, has a near resemblance to marble, is of dark green colour, or reddish; variously streaked, and spotted with lighter green, red, brown, and yellow._

_It is found in beds, and in a massive state; is translucent at the edges; and, when pounded, the powder feels soapy to the touch._

There are few stones likely to prove more valuable in ornamental architecture, both for beauty and durability, than this. It admits of an excellent polish, which is not easily injured by the effects of air or water. It is also too hard to suffer the same inconveniences of being scratched or broken as marble; and its colours are stated to be indestructible. And such is the size of many of the blocks of serpentine, that columns of almost any dimensions may be wrought out of them.

Of the serpentine obtained from the Island of Anglesea, and lately known by the name of _Mona marble_, a great proportion was sent to London by Messrs. Bullock and Co. who, until the death of Mr. Bullock, had a large warehouse and polishing rooms for it in Oxford─street. The prevailing colours of this stone are red and green. The quarries were worked by them to considerable extent. They manufactured it into chimney pieces, slabs, columns, and other articles; and its great beauty, and its excellence, in many respects, over the generality of marbles, will recommend it strongly to the public notice.

The chief places in which serpentine has hitherto been found are near Bareuth, and Zöblitz, in Saxony; in some districts of Cornwall; about six miles west of the Paris copper mine, in the island of Anglesea; at Portsoy, in Bamffshire, and other parts of Scotland; and at Cloghan Lee, in the county of Donegal, Ireland.

At Zöblitz there are some extensive manufactories, in which serpentine is made into vessels and ornaments of various shapes, that are carried for sale over nearly all parts of Germany. Several hundred persons are there employed in the working of this stone.

The name of serpentine is derived from some of the varieties appearing coloured and spotted like a serpent’s skin. This stone, when found intermixed with primitive limestone, or crystalline white marble, differs in no respect from the celebrated _verde antique_ marble (149).

133. _POTSTONE, or LAPIS OLLARIS, is a greenish grey stone, unctuous to the touchy and so soft when first taken from the quarry as to yield to the pressure of the nail, yet not easily broken._

_It is found in a massive state._

In consequence of the softness and tenacity of this stone, it can be turned upon a lathe, and otherwise cut and wrought with great ease. Hence, in Egypt, Lombardy, Norway, and other countries where it is found, it is formed into various kinds of culinary vessels and lamps, which harden in drying, and are capable of withstanding the strongest action of fire. Vessels of this description were known to the ancients; and are particularly mentioned by Pliny, the Roman naturalist, who speaks of some that were highly wrought being very valuable.

Potstone is used in some countries for the lining of stoves, furnaces, and ovens; and it is so durable as to have, in some instances, stood unimpaired for several hundred years.

On the banks of the Lake Como, there were some extensive quarries of potstone, which had been worked from the beginning of the Christian era. These quarries, however, fell in, on the 25th of August, 1618, and destroyed the neighbouring town of Pleurs; which had previously obtained by means of them an annual revenue of about sixty thousand ducats.

134. _COMMON, or VENETIAN TALC, is an earthy stone, capable of being divided into plates or leaves, which are soft and unctuous to the touch, somewhat transparent, and usually of greenish silvery white colour._

_It leaves a white trace when rubbed upon any object._

_Mica and talc have a near resemblance to each other; but the plates of the former, when bent, are elastic, while those of the latter are not._

Venetian talc is very abundant in the Tyrol and the Valteline. In a state of powder it renders the skin soft and shining; a property which appears to have suggested the idea of employing it as the basis of the cosmetic named _rouge_. This is prepared by rubbing together, in a warm mortar, certain proportions of carmine, or extract of the flowers of _carthamus tinctorius_, with finely powdered talc, and a certain portion of oil of benzoin.

The Romans prepared a beautiful blue or purple colour, by combining pounded talc with the colouring fluid of some particular kinds of testaceous animals, that are found among the submarine rocks of the coasts of the Mediterranean. According to Tavernier, the French traveller, the Persians whiten the walls of their houses and gardens with lime, and then powder them with a silvery white kind of talc; which, he says, gives to them a very beautiful appearance. Talc is now used by the Chinese, and was formerly used by the Europeans, in medicine,

135. _INDURATED TALC, or FRENCH CHALK, is a heavy mineral, of close texture, and generally of greenish grey colour; unctuous to the touch, and having a somewhat slaty fracture._

_It is found in a massive state; and leaves a white trace when rubbed upon any object._

This is a well known substance, which is in great request by carpenters, tailors, hat─makers, and others, as the lines that are drawn with it are not so easily effaced as those that are made with chalk, and particularly as they remain unaltered even under water. If lines be traced with it on glass, they remain invisible, or at least are scarcely perceptible by the naked eye, till breathed upon. This, it has been conjectured, in part depends on the comparative softness of the substance with which the impression is made; the condensation of the breath taking place more readily on the glass than on the talc that covers it, and the impression of the talc becoming more apparent by the contrast.

Indurated talc, when reduced to powder, is frequently employed for the purpose of removing stains, occasioned by grease, from silk and cloth. This it does effectually, and, in general, without injuring even the most delicate colour. Like potstone, it is sometimes manufactured into culinary vessels.

This mineral is found in several parts of the continent of Europe; and in Cornwall, Scotland, and the Shetland Islands.

136. _ASBESTOS is a greenish or silvery white mineral, of fibrous texture, which is found in many mountainous countries of the Continent, in the island of Anglesea, and in Scotland. It occurs in shapeless masses, and varies much both in weight and hardness._

The name of asbestos is derived from the Greek language, and signifies that which is inconsumable. This mineral, and particularly a silky variety of it, in long slender filaments, called _amianthus_, was well known to the ancients. They made it into an incombustible kind of cloth, in which they burned the bodies of their dead, and, by which means, they were enabled to collect and preserve the ashes without mixture. In the manufacture of this article they were not able to weave the asbestos alone; but, in the loom, were obliged to join with it linen or woollen threads, which were afterwards burned away.

Incombustible cloth was purchased by the Romans at an enormous expense. Sir J. E. Smith, when at Rome, saw a winding sheet of amianthus in the Museum of the Vatican. It was coarsely spun, but as soft and pliant as silk. The person who attended him set fire to one corner of it; and the same part burned repeatedly with great rapidity and brightness, without being at all injured. This interesting relic was discovered, in the year 1702, in a funeral urn, and contained burned bones, together with a quantity of ashes. It was nine Roman palms long, and about seven in width, and had been deposited in the library of the Vatican by order of Pope Clement the Eleventh.

Cloth made of amianthus, when greased, or otherwise contaminated with dirt, may be cleansed by throwing it into a bright fire. In this process the stains are burned out, and the cloth is restored to a dazzling white colour. Pliny, the Roman naturalist, informs us that he had himself seen table─cloths, towels, and napkins of amianthus taken from the table of a great feast, thrown into the fire, and burned before the company: and by this operation, he says, they became better cleansed than if they had been washed.

The inhabitants of some parts of Siberia manufacture gloves, caps, and purses of amianthus; and in the Pyrenees it is wrought into girdles, ribbons, and other articles. The finest girdles are made by weaving the most beautiful and silky filaments with silver wire. These are much prized by the women, not only on account of their beauty, but from certain mysterious properties they are supposed to possess.

The shorter fibres of amianthus have sometimes been manufactured into paper, but this is too hard for use. It has, indeed, been proposed to preserve valuable documents from fire, by writing them on paper made of amianthus. Such a plan might deserve consideration, if we possessed fire─proof ink; but until this be obtained, the fire─proof paper will be of little use.

When several of the long fibres of this mineral are placed together, they may be formed into wicks for lamps; and it has been asserted that such wicks are incombustible. Kircher, the German philosopher, had a wick made of amianthus which burned for two years without injury, and was at last destroyed by accident. It is said that the inhabitants of Greenland make use of amianthus for the wicks of their lamps.

This substance, although it will long continue unaltered in considerable heat, yet if the heat be much increased it ceases to withstand it, and is melted into a dense kind of scoria. In the island of Corsica asbestos is advantageously employed in the manufacture of pottery. Being reduced into fine filaments, it is kneaded with clay; and vessels made of this mixture are said to be lighter, less brittle, and more capable of sustaining sudden alterations of heat and cold than common earthenware.

CHRYSOLITE FAMILY.

137. _CHRYSOLITE, or PERIDOT, is a soft gem, usually of yellowish green colour, though sometimes it is grass─green, or bluish green, but with a tinge of brown._

_It is generally found in fragments and rounded pieces, and rarely crystallized. In the latter case its regular form is an eight, ten, or twelve─sided prism._

Though scarcely harder than glass, and consequently inferior to most other gems in lustre, these stones are not unfrequently used in jewellery, particularly for necklaces and ornaments for the hair; and, when well matched in colour, and properly polished, their effect is very good. They are, however, too soft for ring stones; for, by wearing, they soon become dull on the surface. But it is said that their lustre may, in some degree, be restored by immersing them in olive oil.

To give the greatest brilliancy to this stone, we are informed by Mr. Mawe, that a copper wheel is used, on which a little sulphuric acid, or spirit of vitriol (24), is dropped; and that, during the process, an highly suffocating odour is given out. But he is of opinion that the most advantageous way of working it would be that in which glass is cut.

Chrysolite is imported from the Levant, and is said to be found in Upper Egypt, and on the shores of the Red Sea.

BASALT FAMILY.

138. _BASALT is a greyish black and coarse grained stone, which is usually found either in globular distinct pieces or in groups of large columns, each of which has from three to eight sides, and is divided horizontally into numerous stones, that very exactly lie upon, or fit into each other._

The most remarkable assemblages of basaltic columns that are known are those called the _Giants’ Causeway_, on the coast of Antrim, in Ireland, and the _Cave of Fingal_, in the island of Staffa, one of the Hebrides, or Western Islands of Scotland.

The former, which is believed by the common people to have been an artificial production, the vast labour of giants who formerly inhabited the country, consists of an irregular group of many thousand jointed pillars. Most of these are of considerable height; are in general five─sided, fifteen or sixteen inches in diameter, and each perfectly distinct from top to bottom, though so closely and compactly arranged that it is scarcely possible to introduce any thing betwixt them. This assemblage of columns extends into the sea to a distance unknown, and along a tract of the sea coast of nearly six miles.

The Cave of Fingal is accessible only by sea, and is formed by ranges of massive basaltic columns, fifty feet and upwards in height. The stone of which these columns are formed very much resembles that of the Giants’ Causeway.

In several parts of the world large masses of basalt are discovered, composing entire insulated mountains, of somewhat conical form. They are considered by some writers as volcanic productions, but the proofs of this are by no means satisfactory.

Amongst the uses to which basalt has been applied, two of the most important are as materials of an excellent and durable kind for building and paving. When burned and pulverized, these stones impart to mortar with which they are mixed the property of hardening under water. They easily melt, without any addition, into an opaque and black glass; and from them, under a certain modification, bottles of olive─green colour, and of extreme lightness, but great strength and solidity, have been formed. Some of the kinds have been advantageously employed as millstones. Basalt is occasionally used by artists for touch or teststones, to ascertain the purity of gold and silver; and goldbeaters and bookbinders, on the Continent, usually make their anvils or beating blocks of it.

Basalt, though harder, more brittle, and less pleasing in its colours than marble, was in considerable esteem among the sculptors of antiquity, on account of its great durability. Many fine works were consequently executed by them in this stone. Pliny, who has described several, states that the columns of it were sometimes so large as to admit of several figures being wrought out of them. The Emperor Vespasian had an entire statue, accompanied by the figures of sixteen children, cut out of a single column of basalt; this statue he placed in the Temple of Peace, and dedicated it to the Nile. The famous statue of Minerva, at Thebes, is described by travellers to have been formed of basalt. Antiques of basalt are always in a much better state of preservation than those of marble. Even such as are dug out of the earth still retain their original polish; and the finest touches of the chisel upon them are still unimpaired.

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ORDER III.—SALINE STONES.

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LIME, OR CALCAREOUS FAMILY.

139. Lime, after it has been freed from extraneous matters by burning, is a mineral of whitish colour, and pungent, acrid, and caustic taste. It has the property of changing vegetable blue colours to green, and of corroding and destroying animal substances.

This mineral is found in nearly every country of the globe: but, in a native state, has not hitherto been discovered except in combination with some acid.[3] The process of purifying lime, or depriving it of the acid with which it is combined, is by burning. This is done in a large kind of furnace, called a _kiln_, where the limestone and fuel are heaped in alternate layers. After it has gone through this process it is called _quick─lime_, and has the above─mentioned appearance and qualities.

Footnote 3:

With _carbonic acid_ (26) it forms common limestone, marble, chalk,
and some other substances; with _sulphuric acid_ (24) it constitutes
alabaster, or gypsum; and with _fluoric acid_ (27) it becomes that
beautiful production, the Derbyshire spar.—All these, having lime for
their bases, are denominated CALCAREOUS SUBSTANCES.

The uses of lime are numerous and important. The principal of these is in the formation of _mortar_, or cement for buildings. For this purpose it is first _slaked_, by having water poured upon it: a violent heat is thereby excited, and the lime falls into powder: it is then formed into paste by working it with water and sand. This, when dry, becomes extremely solid, hard, and durable. Various examples might be mentioned of buildings nearly two thousand years old, where the lime is, at this day, as hard as the stones which it cements together. Lime is also used for agricultural purposes: when spread upon land it is supposed to hasten the dissolution and putrefaction of all kinds of animal and vegetable substances, and to impart to it a power of retaining the moisture which is necessary for the vigorous growth of corn or grass. It is employed in the refining of sugar, in the manufacture of soap, in the melting of iron, and by tanners, in a state of solution, for dissolving the gelatinous parts of skins, and removing the hair from them. The manufacturers of glue mix it with that article, for the purpose of adding to its strength, and preventing its becoming flexible by the absorption of moisture. This mineral, if well dried, pounded, and mingled with gunpowder, in the proportion of one pound to two, is of great utility in the rending of stones and rocks: the mixture, it is said, will cause an explosion equal in force to three pounds’ weight of gunpowder. Lime, if swallowed or inhaled, is a virulent poison. Hence persons employed in lime─works are subject to very distressing complaints; and hence, if bread be adulterated with lime, it is extremely injurious. Notwithstanding this pernicious quality, lime is of considerable use in medicine. It is chiefly given in a state of solution, and in the proportion of half a pound of quick─lime to twelve pints of boiling distilled water. This preparation is called _lime water_.

The superb basin of Lampi, one of the principal reservoirs which furnishes the canal of Languedoc with water, was, some years ago, found to leak at the junction of the stones. The engineer who had the direction of the works caused lime to be slacked in the water. This, passing through the apertures betwixt the stones, formed a crust, or very white covering, over its whole surface, of so hard and durable a nature, that it now constitutes one solid and undivided substance, which the water cannot penetrate.

CARBONAT OF LIME.

140. _COMMON LIME is a variety of carbonat of lime, or of lime in combination with carbonic acid (26), which is harder and heavier than chalk, usually of a greyish colour, and is always found in a massive state._

Vast mountains of limestone occur in several countries of the globe; but no where is lime more abundant than in some parts of England and Wales. It forms, in particular, nearly the whole mountainous districts of Derbyshire and Shropshire, and encloses, in its substance, numerous veins of lead ore, calamine, and other important mineral productions.

Its uses have been already described (139).

141. _CHALK is a white or yellowish kind of limestone, too well known to need any description._

It is found abundantly in many of the southern counties of England, and is usually procured from large open places, called chalk─pits, by digging. In some parts of Kent, however, the workmen save themselves, in this respect, much trouble. They undermine the sides of hills to a certain depth, then dig a trench at the top as far distant from the edge as the mining extends at the bottom. This trench they fill with water, which soaks through during the night, and the whole mass is thereby loosened, and falls down before morning.

The harder and more compact kinds of chalk are cut into blocks, and used as building stones. When burned and formed into lime, chalk becomes an excellent mortar: nearly all the houses in London are cemented with chalk mortar. It is also used as lime in agriculture. As it readily imbibes water, it is used by starch─makers, chemists, and others, to dry precipitates upon. With isinglass or the white of eggs it forms a valuable lute or cement. By artists it is in request for the construction of moulds to cast metals in; and by carpenters and others, as a material to mark with. Chalk is one of the most useful absorbents that are employed in medicine: it likewise gives name to an officinal mixture, to a powder, and a potion.

When pounded and cleared from gritty particles, it has the name of _whiting_. In this state it is used for the cleaning and polishing of metallic and glass utensils; for whitening the ceilings of rooms, and numerous other purposes. _Spanish white_ is the same substance cleansed with peculiar care; and the _Vienna white_, which is used by artists, is perfectly purified chalk.

142. _MARBLE is a compact and close─grained kind of limestone; so hard as to admit of being polished. It is this quality which principally distinguishes it from other calcareous substances._

Although nearly all the numerous kinds of marble may be burned, and thus converted into quick─lime, their use in ornamental architecture, &c. is so important as, in general, to prevent their application to the inferior purpose of mortar. Marble has been known from a very early period. The Book of Esther, in the Old Testament, describes the palace of Ahasuerus to have had “pillars of marble,” and the pavement of “red, and blue, and white, and black marble.”

It would be impossible, in an elementary work like the present, to describe, or even to enumerate, all the different kinds of marble which were known to the ancients, or are known to the moderns. But it is, perhaps, requisite that an account should be given of some of the most important of them.

_GREEK MARBLES._—143. PENTELIC MARBLE _is of beautiful white colour, and nearly resembles the Parian marble_ (145) of the Italians; but it is in coarser granulations. Sometimes it is splintery. It was obtained from quarries on Mount Pentelicus, near Athens, and was generally preferred, by the Grecian artists, to Parian marble. The Pantheon was built entirely of Pentelic marble; and many of the Athenian statues, and works carried on near Athens during the administration of Pericles, were executed in it. Dr. Clarke, however, has observed that while the works wrought of Parian marble remain perfect to the present time, those of Pentelic marble have been decomposed by the atmosphere, and sometimes exhibit a surface as rude and earthy as common lime─stone. There are numerous examples of Pentelic marble in those works of Phidias which form the Elgin collection in the British Museum.

144. GREEK WHITE MARBLE.—_The Marmo Greco, of Italian artists, is of snow─white colour, in fine granulations_; and somewhat harder, and consequently capable of higher polish, than most other white marbles. It is found near the river Coralus, in Phrygia.

_ITALIAN MARBLES._—145. PARIAN MARBLE _is of snow─white colour, inclining to yellowish white_. It is obtained from quarries in the island of Paros, is finely granular, and, when polished, has somewhat of a waxy appearance. Parian marble hardens by exposure to the air, and is one of the most permanent kinds that is known. Varro and Pliny each state that it was named _lychnites_, by the ancients, from a Greek word signifying a lamp, because it was generally hewn in quarries by the light of lamps. The finest Grecian sculpture that has been preserved to the present time is of Parian marble. The principal statues of it now extant are the Medicean Venus, the Diana Venatrix, and Venus leaving the Bath. It is also Parian marble on which the celebrated tables at Oxford are inscribed.

146. CARRARA MARBLE, the purest of all the kinds with which we are acquainted, is to this day obtained from quarries near the town of Carrara. _It is of brilliant white colour, has a granular texture; and, when broken, sparkles like sugar._ This marble, which is almost the only one in use by modern sculptors, was also quarried and wrought by the ancients.

It is susceptible of a high polish, and is applicable to every species of sculpture, except when, as is too often the case, dark veins intrude, and spoil the beauty of the work. In the centre of the blocks a beautiful kind of rock crystals, called _Carrara diamonds_, are sometimes found.

During the late war with France, the exportation of statuary marble from the countries under the dominion of Buonaparte was prohibited; and, at one time, it became so scarce in England as to be sold at the rate of more than seven guineas per cubic foot. The block of marble for the statue of his late Majesty in the great Council Chamber at Guildhall, London, was stated by the public prints to have cost twelve hundred guineas.

147. LUNI MARBLE _is a snow─white, compact, and finely granular variety_, which was obtained by the ancients from quarries on the coast of Tuscany. It was preferred by the Grecian sculptors, both to the Parian and Pentelic marbles; and it is usually supposed that the Belvidere Apollo, as well as the Antinous of the Capitol, was wrought out of this marble. There is now found at Luni a white marble, variegated with red spots and dots.

148. GREEN ANTIQUE MARBLE, or VERDE ANTIQUE _of the Italians, is a mixture of white marble and green serpentine_ (132). This is believed to have been obtained from some part of Italy, but the quarries are not now known.

149. SIENNA MARBLE _is of close texture, and yellowish colour, disposed in large irregular spots, surrounded with veins of bluish red, passing sometimes into purple_. It is not uncommon in the vicinity of Sienna, and is in great request, throughout Europe, for chimney─pieces and ornamental furniture.

150. BROCATELLO MARBLE is somewhat like the last; but is also irregularly marked with various shades of red, and, in some parts, with white.

151. MANDELATO MARBLE _is of light red colour, with yellowish white spots_. It is found at Lugezzana, in the Veronese. Another variety, bearing the same name, occurs at Preosa.

152. VERDE DI PRATO MARBLE _is a green marble, marked with darker green spots_, which is found near the town of Prato in Tuscany.

153. LAGO MAGGIORE MARBLE _is a beautiful kind, white, with black spots and dots_. It has been employed for decorating the interior of many churches in the Milanese.

154. BRETONICO MARBLE.—This beautiful marble, which is found near the village of Bretonico, in the Veronese, _is varied with yellow, grey, and rose colour_.

_FRENCH MARBLES._—155. Many valuable kinds of marble are obtained from different parts of the French territory.

156. CAMPAN MARBLE.—Three kinds of marble are known by this name, all of them procured from immense quarries at Campan, near Bagnere, in the Pyrenees. The first, called _Green Campan_, is of pale sea─green colour, and exhibits, on its surface, lines of much deeper green, forming a kind of net─work. The second, called _Isabel Campan_, is of delicate rose colour, with undulating green veins. The third variety, the _Red Campan_, is of deep red colour, with veins of still deeper red. The green variegations in this stone are formed by a talcy mineral, intermixed with the lime─stone.—The Campan marble is well adapted for slabs, tables, chimney─pieces, and other ornamental purposes in the interior of buildings; but, if exposed to the weather, the talcose substances perish, and leave hollow spaces which render its surface rough and uneven.

157. GRIOTTE MARBLE _is of a deep brown colour, with blood─red oval spots, formed by shells_. Its name has been obtained from its brownish colour, being similar to that of the cherries that are called by the French _griotte_. This marble has, of late, been much used in the decoration of public monuments, and in splendid furniture, in France. Some of the ornaments of the Triumphal Arch of the Carousel are made of it. The department of Herault is the part of France from which it is obtained. It sometimes contains large white veins, which destroy the harmony of the other tints.

158. MARQUESE MARBLE.—This, which is obtained from quarries, near the village of Marquese, between Calais and Boulogne, is marked with _different shades and variegations of white and brown_. Of this marble Buonaparte commenced a magnificent column on the heights near the sea, at Boulogne, to commemorate his victories; but, since his dethronement, the erection of this structure has been discontinued.

159. SARENCOLIN MARBLE _is distinguished by exhibiting large zones, and angular spots of yellow or blood─red colour_. It is found at Sarencolin, in the High Pyrenees.

160. ST. BEAUME, or LANGUEDOC MARBLE, _is of light red colour, marked with white and grey zones, formed by madrepores_. The eight columns which adorn the Triumphal Arch, in the Carousel at Paris, are of this marble. It is obtained from quarries at St. Beaume, in the department of Aude.

161. BRECCIA MARBLE OF THE PYRENEES.—One kind of this marble contains black, grey, and red, middle─sized spots in a brownish red ground. It admits of a good polish. Another kind has an orange─yellow─coloured ground, containing small fragments of snow─white colour. Both these are found in the Pyrenees.

_SPANISH MARBLES._—162. Few countries are more productive of marble than Spain; and in few countries are the public monuments and buildings more profusely decorated with marble. The vault of the theatre of Toledo is supported by 350 marble columns; and an ancient mosque at Cordova is ornamented with 1200 columns, most of which are of Spanish marble. The palace and church of the Escurial, and many of the churches in Madrid, are decorated with marbles of the most beautiful description.

163. WHITE SPANISH MARBLE.—Near Cordova; at Filabres, three leagues from Almeria, in Grenada; and in some other parts of Spain, white marble is obtained, which is susceptible of a good polish, and is well adapted to the general purposes of sculpture.

164. SEVILLE MARBLE _is a beautiful red variety, with shining red and white spots and veins_. In the vicinity of TORTOSA is found a kind of marble which has a _violet ground, spotted with bright yellow_; and near GRENADA a marble of _green colour_, which somewhat resembles the celebrated verde antique (149).

165. SPANISH BRECCIA.—There are several beautiful varieties of breccia in Spain. At Riela, in Arragon, there is one, composed of angular portions or fragments of black marble, embedded in a reddish yellow base. The breccia marble of Old Castile is of bright red colour, dotted with yellow and black, and encloses fragments of pale yellow, brick─red, deep brown, and blackish grey colour.

_GERMAN MARBLES._—166. Germany abounds in marbles, and affords many kinds which are remarkable both for beauty and singularity. Of these the kind best known is

167. LUMACHELLI MARBLE.—_This exhibits beautiful iridescent colours, which are sometimes prismatic internally, but more commonly of various shades of red or orange_; whence it has also obtained the name of _fire marble_. Few kinds of marble are more generally admired than this. It has a dark ground, and is marked throughout with the appearance of small whitish shells, which, in certain parts, refract the most beautiful and brilliant colours. This marble is cut into the tops and bottoms of snuff─boxes, and several other ornamental articles. It is found in veins at Bleyberg, in Carinthia.

168. Many beautiful kinds of marble are obtained from the island of SICILY, particularly one called _Sicilian jasper_, which is red, with stripes like ribbons, white, red, and sometimes green. SWITZERLAND abounds in marbles; PORTUGAL, SWEDEN, and NORWAY afford few. In the RUSSIAN EMPIRE many have been noticed, particularly among the Uralian mountains. The late Empress Catharine caused an immense palace to be built for her favourite Orloff, which is entirely coated, both inside and outside, with marble. She built the church of Isaac with marbles of different kinds, on a vast space, near the statue of Peter the Great, in Petersburgh. We are at present very imperfectly acquainted with the marbles of ASIA. Dr. Shaw mentions a red marble obtained from Mount Sinai; and Mr. Morier, in his journey through Persia, speaks of a beautiful translucent kind which he calls _marble of Tabriz_, and the colours of which are light green, with veins sometimes of red, sometimes of blue. He says it is cut into large slabs, some of which he describes to have measured nine feet in length, and five feet in breadth.—No account has hitherto been published of the marbles of AFRICA.—In the United States of AMERICA many kinds of marble have been discovered, some of which have been wrought, and polished; but very imperfect descriptions have yet been given of them.

169. Few countries produce a greater variety of excellent marbles than the BRITISH ISLANDS. Although these marbles are seldom noticed much beyond the limits of the districts in which they occur, many of them are admirably adapted for ornamental purposes; particularly for slabs and chimney─pieces. It is much to be regretted that we should send to foreign countries for stones which, in many instances at least, could certainly be as well supplied from our own. The following is an enumeration of a few of the most important kinds.

_ENGLISH MARBLES._—170. PETWORTH MARBLE, when cut into slabs, is equal, both in beauty and quality, to many of the marbles imported from the Continent. The Earl of Egremont has, at Petworth, several chimney─pieces formed of it. Much of this marble was used in the cathedral church of Canterbury. The pillars, monuments, vaults, pavement, and other parts of that venerable structure, have been formed of it. The archbishop’s chair is an entire piece of Petworth marble. This marble is found in greatest perfection upon an estate of the Earl of Egremont, at Kirdford. It lies at the distance of from ten to twenty feet under the surface of the ground, and in flakes or strata nine or ten inches in thickness. Petworth marble is also an excellent stone for walls; and, for paving, it cannot be excelled. When burned, it also constitutes a valuable manure, superior, as some farmers imagine, even to chalk.

171. PURBECK MARBLE is obtained from the island of Purbeck, in Dorsetshire. _It is of dark colour, and contains numerous small round shells_, which, when it is cut and polished, mark it with roundish variegations of brown, dark green, and grey. This marble was formerly more used than it is at present. Several of the small columns, and many of the monuments, in the churches of Dorsetshire, and the adjacent counties, are formed of it. But it is not so durable as many other kinds. Wherever it is long exposed to the weather, the surface cracks, splits off, and becomes defaced.

172. BABBICOMBE MARBLE is one of the most beautiful kinds that is found in any country. _It varies in colour, from light brown to deep red_; and large slabs of it have been obtained that are elegantly and diversely marked, some in streaks, others in spots, and others in different coloured shades.

This kind is quarried at Babbicombe, in Torbay, Devonshire, and is extensively manufactured into chimney─pieces in the West of England. An attempt was lately made to introduce it in London; but, from its not being the production of a foreign country, this has failed of success.

173. DERBYSHIRE MARBLE.—There are, in Derbyshire, several kinds of marble, most of which contain an abundance of fossil shells, and other remains of marine animals. At Wetton, near Ashbourne, a beautiful kind is obtained, of greyish black colour, which contains a vast number of whitish and very minute shells. This has the name of _bird’s eye marble_. Near Monyash a beautiful variety is found, of a cheerful colour, inclining to brown red, and full of large marine figures in all directions; these, when the marble is cut, appear white, and afford a pleasing contrast.

174. KENDAL MARBLE.—Some varieties of black, grey, and brown marble, are wrought near Kendal, in Westmoreland. These somewhat resemble the Derbyshire marbles; and, like them, are manufactured into chimney─pieces, and ornamental slabs for houses. Several of the slabs are found to contain corallines, and the remains of other marine animals, which vary their appearance in a very pleasing manner.

The MONA MARBLE is a species of serpentine intermixed with white limestone: it has been already described (132).

_SCOTTISH MARBLES._—Scotland affords many valuable and beautiful varieties of marble.

175. TIRIE MARBLE.—Few of the British kinds of marble have been more admired than that obtained from Tirie, one of the Western Islands of Scotland. _It is of a reddish, sometimes a delicate rose─coloured tint, and sometimes white; and is always intermixed with other minerals which add to its beauty._ The most common of these is of black colour, and called hornblende; the others are pale green sahlite, blackish brown mica (123), and green chlorite. In some varieties the hornblende is more abundant than the marble.

176. ASSYNT MARBLE.—At Assynt, in Sutherland, _a white marble_ has been discovered, which is perfectly solid and pure, and entirely free from blemishes or stains. Blocks or slabs of it may be cut of almost any size that can be required. This marble acquires a smooth surface, but remains of a dead hue; whence, of course, its uses as an ornamental marble are much circumscribed.

177. ISLE OF SKY MARBLE.—There is found in the Isle of Sky a marble of pure white colour, which appears capable of yielding large and valuable blocks. Its fracture is granular and splintery, and its texture fine. It is harder, heavier, and more compact than the marble of Carrara (146); and is apparently well fitted for all the purposes of sculpture. But it has the defect of being very unequally hard. While some parts of the stone are nearly as easy to work as that of Carrara, other parts are so hard as to add a charge of near fifty per cent. to the cost of the working.

178. SUTHERLAND MARBLE.—Some beautiful specimens of marble of dark brown colour, veined with whitish, light red, or light brown, have lately been brought from the county of Sutherland. These appear of close texture, are susceptible of a beautiful polish, and are capable of being wrought into extremely beautiful slabs for chimney─pieces and other ornamental purposes.