tint; and some are found of a bluish color, and some black. For the valuation of diamonds an arbitrary rule has been given, which is, however, little regarded in actual sales of the most costly of these gems. Purchasers for such being few, the only real rule adopted, as in the sale of many other commodities, is to demand the highest price there is the least probability that one may be induced to pay. The mere statement of the rule is sufficient to show its indefiniteness. It is to multiply the square of the weight in carats by a sum varying according to the state and quality of the stone. If clear and of good shape, this sum is £2; if perfect and well cut, £6 or £8 for the brilliant or rose, but a lower figure for the table. The rate is now $15 in place of the £2 above, and a specimen brilliant is worth $75. For diamonds of moderate size the rates vary as little as those of exchange between countries. They follow from the natural proportions in which diamonds are found. Diamonds weighing over 10 carats are generally esteemed at a higher proportional rate than the smaller sizes; yet the latter can commonly be sold at higher proportional rates, on account of the few purchasers for those of large size. In the great sale of jewels in London in 1837, on the distribution of the Deccan booty obtained by the army of the marquis of Hastings, the splendid Nassuck diamond, weighing 357 grains, and of the purest water, brought only £7,200. The present value of diamonds may be inferred from the price paid in Dec. 1858, for a stone weighing 61 carats, £33,000. A pair of drop-shaped diamonds for ear-rings were bought at the same sale for £15,000. A steady increase has taken place since the last century, and a much more rapid increase in the price of fine gems is to be expected, from the increased demand and diminished supply. It is an interesting fact that the finest gems of commerce are now in great part supplied by the old jewels of Portuguese, Spanish, French, and English families, the proportions from each nation in the order named; and that the best market for them is now the United States.-The art of cutting and polishing probably originated in Asia, at a very early period, but was first introduced into Europe about the middle of the 15th century by Louis Berquen of Bruges, who accidentally discovered that by rubbing 2 diamonds together their surfaces might be abraded. The powder obtained in this way is used for polishing the stone. Diamond cutting was for a long time a monopoly in Holland, and the business is at the present day mostly confined to Amsterdam. The process, which consists of grinding down the surfaces as well as cutting, is slow and tedious, and being done entirely by hand, occupies for a single stone the continual labor of months. The Pitt diamond indeed required 2 years for the completion of the process. Two diamonds are employed, each cemented into the end of a stick or handle, a model in lead being taken of the one to be cut, by which the faces are determined. The stones are then rubbed together with a strong pressure, being

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held over a metal box having a double bottom, the upper one perforated with small holes, through which the diamond dust falls. This is afterward carefully collected, mixed with vegetable oil, and used for polishing the gem upon a revolving cast-iron disk. When a large piece is to be removed from the stone, it is sometimes cut off by means of a steel wire covered with diamond powder, and sometimes by the use of a chisel and hammer, though in this way there is danger of destroying the stone. The workman should understand perfectly the position of the cleavage planes, as it is only upon them that pieces can be removed by the chisel. The forms usually adopted in cutting the diamond are the brilliant, the rose, and the table. The first shows the gem to the best advantage. It is composed of a principal face called the table, surrounded by a number of facets, which is all that is visible above the bezil when set. The stone in depth below the bezil should be equal to half its breadth. On the under side it terminates in a small table, which is connected with the upper surface by elongated facets. As the brilliant is the most economical of material, and shows the stone most advantageously, it is usually preferred to any other. The rose, which is very brilliant, is flat below and cut into facets entirely over the upper surface. The table is least beautiful, and is used mostly in India for thin stones with a large surface, which are ornamented by being cut into facets at the edges.-Among the most celebrated diamonds known, that obtained by Mr. Pitt, governor of Madras, is perhaps one of the finest and most perfect. It is known as the regent. Its weight before cutting was 410 carats, and by this process, which occupied 2 years, it was reduced to 136 carats, and was purchased by the regent duke of Orleans in 1743 for $675,000. Its present value is estimated at $1,000,000. It was placed by Napoleon in the hilt of the sword of state. A splendid diamond recently found in Brazil, and imported into France, is called the "Star of the South." It weighs in its rough state 254 carats. Its general form is a rhomboidal dodecahedron, and upon its faces are impressions which appear to have been made by other diamonds, so that the whole was probably a group of diamond crystals. The famous diamond in possession of the king of Portugal is also from Brazil. If genuine, of which there is some doubt, its value, according to the rule of computation, should be $28,000,000, weighing as it does in the rough 1,680 grains.-The famous Koh-i-noor or "Mountain of Light" is now in possession of the queen of England. This wonderful stone, interesting alike for its historical associations and for its intrinsic beauty, was, according to Indian tradition, obtained before the Christian era from one of the mines of Golconda. From the rajah of Oojein, who seems to have possessed it at the beginning of the Christian era, it passed to successive sovereigns of central India, and in the early part of the 14th century was added to the treasures of Delhi by the Patan monarch Aladdin. It remained in possession of the rul

ing families of the empire until the irruption of the Persian conqueror Nadir Shah, who saw it glittering in the turban of the vanquished Mohammed Shah, and proposing an exchange of head dress as a mark of friendship, bore it away with him, and gave it the name by which it is still known. After the assassination of Nadir it passed through the hands of Ahmed Shah of Cabool to Shah Soojah, who paid it as the price of his liberty to his conqueror Runjeet Singh, the "lion of the Punjaub," in 1813. On the annexation of the Punjaub to the East India company's territory in 1849, it was stipulated that the Koh-i-noor should be surrendered to the queen of England, to whom it was accordingly delivered by the company, July 3, 1850. At this period its weight was 186 carats. It was exhibited at the crystal palace in London in 1851, where it attracted universal attention; but when found to exhibit an inferior display of colors to its glass model, and that it was necessary to surround it with a number of vivid lights to develop its colored refractions, multitudes turned away disappointed from the worldrenowned "Mountain of Light." An examination was made of it by scientific gentlemen, with reference to the propriety of recutting the gem. After obtaining the opinions of skilful cutters at Amsterdam, it was decided that the attempt should be made, though some fears were entertained as to its success. Being the largest diamond cut in Europe for a long time, it was a work of no common interest. Orders were given that the proper machinery should be prepared, and a small steam engine was procured for the purpose. The duke of Wellington commenced the work. The stone being imbedded in lead, excepting only that portion which was first to be cut, he held it firmly against a rapidly revolving wheel, which by its friction removed the angle exposed, and thus the first facet of the fresh cutting was accomplished. The operation was continued and successfully completed by careful and experienced workmen. Now, the splendid Koh-i-noor, freed from all blemishes and defects, blazes brilliantly among the crown jewels of the sovereign of England. The diamond so long in possession of the sultan of Matan, of the island of Borneo, is remarkable for its size and purity. It weighs 367 carats, and should be worth at least $3,500,000. It is shaped like an egg with an indented hollow in the smaller end. It was discovered at Landak. The Orloff diamond purchased for the empress Catharine of Russia is about the size of a pigeon's egg, and weighs 195 carats. It is said to have formed the eye of a famous idol in a temple of Brahma at Pondicherry. A French deserter robbed the pagoda of this valuable stone. After passing through the hands of various purchasers, it came into the possession of a Greek merchant, who received for it from the empress $450,000, an annuity of $20,000, and a title of nobility. The Austrian diamond is of a beautiful lemon color, and cut in rose; its weight is 139 carats. Its

value is less than it would be but for its color and the form in which it is cut, ranking as worth $500,000 instead of $750,000. The most valuable diamond found in the United States was picked up by a workman at Manchester, on the banks of the James river, opposite Richmond, in 1856. The locality is in the tertiary formation, and the diamond originally belonged, no doubt, to the gold region up the river. It is of curvi linear octahedral form, specific gravity 3.503, and weighs 23.7 carats. It is lightly chatoyant, and would probably cut white; but an original flaw was increased by the rough treatment it received from those into whose hands it fell, so that its value was greatly deteriorated. It is now in possession of Prof. Dewey. Another valuable diamond, owned by Thomas G. Clemson, Esq., was found among the gold washings of North Carolina about the year 1842. This was of curvilinear form, and was set without cutting. Others of less importance have been found in Georgia.-The imitation of diamonds has been carried to an astonishing degree of perfection among the French. M. Bourguignon has been especially successful in this manufac ture. The sand employed for the production of his splendid diamonds is procured from the forest of Fontainebleau, and forms a considerable article of trade. The setting of these mock stones is always of pure gold, and of the newest fashion, and the ornaments when completed rival in delicacy and lustre the purest diamonds which nature has produced, and only by the closest inspection can the difference be detected. The chief objection to them is their lişbility to become dull in time by deliquescence.— The process of collecting diamonds is similar to that of collecting gold in the alluvial deposits The coarse gravel and rolled pebbles derived from the primary and metamorphic rocks, form the lowest stratum among the sands and clays of the alluvium. This stratum, resting upon the surface of the rock, is the repository alike of gold and of diamonds. It is laid bare in the beds of the streams, when these cease to flow in the dry season, or are drawn off by sluices made for the purpose. From these beds, as well as from excavations in the bottom, the gravel is removed, to be washed when conve nient. This in Brazil is usually in the rainy season, and the work is done in a long shed, through which a stream of water is conveyed, and admitted into boxes in which the gravel is washed. A negro works at each box, and inspectors are placed to watch the work, and to prevent the laborers from secreting the dismonds. It is the custom to liberate the negro who finds a diamond weighing 17 carats. Dr. Beke, in a paper read at a meeting of the British association, relates that a slave in Brazil seeking for diamonds in the bed of a river broke with his iron bar through a crust of silicious materials, cemented together by oxide of iron, in which he discovered a bed of diamonds, which were afterward sold for $1,500,000. This immense quantity, being carried to England, so

DIAMOND

overstocked the market that few of the English houses were able to stand up against it.-Beside their use as ornaments, diamonds are applied to several practical purposes. Those that are unfit from their imperfections for jewelry, are sold under the technical name of bort. They are crushed to fine powder in a steel mortar, and used for coating the metallic disks employed by lapidaries for producing flat surfaces on precious stones of great hardness. The fine splinters are made into drills, for piercing small holes through rubies and other hard stones. The property possessed by the diamond of cutting glass is due not merely to its extreme hardness, but to the peculiarity of its crystallization in rounded faces and curvilinear edges. The natural crystal only is suitable for this purpose. According to Dr. Wollaston, many hard stones, and even flint cut in this form, possess the same property, but soon lose it in use, for want of hardness. Small microscopes of a single lens, and of great power and clearness, have been cut out of diamonds.-The diamond exhibiting the physical properties of matter in their highest state of perfection, and proving after all to be of the simplest chemical composition, it has been a matter of no little scientific interest to study the peculiarities of its construction, and to determine if possible the secret processes by which nature has elaborated the most perfect gem from so homely a substance as charcoal. Its high value has stimulated these researches, in the hope of individual profit by its artificial production. But though more complicated forms of matter have been successfully reproduced, carbon has not yet been made to attain the simple perfection of the diamond, unless it be in crystals invisible to the naked eye; nor have we yet learned from what department of nature's works the material has been taken, that has been so beautifully perfected. The vegetable kingdom may have furnished it, after itself receiving it from the atmosphere, or it may have been unlocked from those repositories of carbon shut up from remote geological periods in the carbonic acid of the calcareous rocks, or from such collections of fossilized plants as are now seen in various stages of change to mineral substance. But if the direct object of these researches has not been attained, the forces which have acted upon it to give to it some of its peculiarities have been partially determined, as also a previous condition in which it must have existed. Sir David Brewster, from the exhibition of polarized light around the minute and irregular cavities in diamonds, has concluded that the substance has once been in a soft state, and compressed in these parts by the expansive action of a gas or fluid contained in the cavities; and as various circumstances indicate that this softness was not the effect of either solvents or heat, he is of opinion that, like amber, the diamond is a vegetable substance, slowly consolidated into a crystalline form. The nearest approach to its reproduction has been in the experiments of M. Desprétz, announced in the

year 1853. By long continued voltaic action, carbon free from every trace of mineral substance, prepared from crystallized sugar candy, was made to deposit microscopic crystals in black octahedrons, in colorless translucent octahedrons, and in colorless and translucent plates, the whole of which had the hardness of the powder of the diamond, and which disappeared in combustion without leaving any perceptible residue. Being, however, only in powder, it was impossible to isolate and weigh these crystals, or to determine their index of refraction and angles of polarization. It is said that a similar result has been obtained by decomposing a mixture of chloride of carbon and alcohol by weak galvanic currents.-The principal English works on the subject are D. Jeffrey's "Treatise on Diamonds and Pearls" (8vo., London, 1750); I. Mawe's "Treatise on Diamonds and Precious Stones" (8vo., London, 1826).

DIAMOND DISTRICT, a part of the district of Serro Frio, in the province of Minas Geraes, Brazil, famous for the production of diamonds. It is a mountainous tract, not far from Villa do Principe, extending about 16 leagues from N. to S. and 8 from E. to W. The diamonds were first discovered here by a company of gold miners in 1730. At first they were ignorant of the value of the gems, and threw away many of them as useless. Others were sent to the governor of Brazil, who supposed them to be curious crystals. A few of the stones having been carried to Lisbon were shown to the Dutch consul, who recognized them as diamonds, and had them transmitted to Holland. Immense numbers of the gems were now exported from Brazil, and the Portuguese government soon took measures to secure a monopoly of the val uable trade. The district was surrounded by lines of demarkation, which were guarded with the utmost strictness. No one was permitted to pass these in either direction without a permit from the intendant of the mines, and travellers leaving the diamond ground were obliged to submit to a thorough examination of their persons, baggage, and horses. A peculiar system of police was established for the regulation of the district, and stringent laws were passed to provide for the registering of the inhabitants, the admission of settlers, the erection of inns and shops, and the punishment of infringements of the government monopoly. The diamond mines were at first rented to private individuals, but the frauds and violations of contract of which these persons were constantly guilty induced the government to take the matter into its own hands, and the mines were long worked under the direction of officers of the crown. The precious stones are found in a kind of gravel, called cascalhão, which is dug up and removed to a convenient place for washing. A shed, about 25 or 30 yards long and 15 wide, consist ing simply of upright posts and a thatched roof, is erected over the spot where the heaps of cascalhão are to be deposited. Through the centre of this shed is conducted a stream of

water, on one side of which is a range of sloping troughs, each about 3 feet wide, and communicating with the stream at the upper end. Opposite to the troughs are high chairs placed at equal distances for the overseers, or feitores. A slave stations himself in each trough, and with a short-handled rake draws up a pile of 50 or 80 pounds of cascalhão. He lets in water upon this, to wash away the earthy particles, and after throwing out the largest stones, examines the rest with great care for diamonds. As soon as he finds one, he stands upright, claps his hands, and holding it between his finger and thumb shows it to the overseer, who receives it from him, and places it in a bowl half full of water, suspended from the centre of the structure. The mines are now open to all who choose to invest their capital in them, and the cost of working them has been estimated at about $8 per carat. They give employment and support to about 10,000 persons.

DIAMOND HARBOR, a roadstead in the river Hoogly, presidency of Bengal, British India, 29 m. below Calcutta. It was the first place in Bengal acquired by the East India company, and is now a shipping depot. The climate is very unhealthy; the neighboring swamps exhale the most noxious vapors, and the night dews are remarkably heavy. An excellent road and an electric telegraph connect the place with Calcutta.

DIANA, an ancient Italian divinity, identified by the Romans with the Artemis of the Greeks. Servius Tullius is said to have introduced her worship at Rome, dedicating to her a temple on the Aventine. As goddess of light she represented the moon. The root of her name seems to be the same as that of the word dies. In images and legends of a later period she fully answers to the Grecian Artemis. (See ARTEMIS.)

DIANA OF POITIERS, duchess of Valentinois, mistress of Henry II. of France, born Sept. 3, 1499, died in Anet, April 22, 1566. She was maid of honor to Queen Claude, and when her father, the count of St. Vallier, had been condemned to death for favoring the escape of the constable Bourbon, she so touched the heart of the susceptible Francis I. by her tears and beauty, that the punishment was commuted. At the age of 13 she became the wife of Louis de Brézé, count of Maulevrier, by whom she had 2 daughters. In 1531 her husband died, and Diana, putting on a widow's weeds, expressed a resolve to wear them to her grave; but this did not prevent her when nearly 40 years old from becoming the mistress of the dauphin, afterward Henry II. The duchess of Etampes then possessed the affections of Francis I., and the 2 favorites divided the court until the accession of the dauphin, when Diana's rival was sent into exile. Diana now became almost mistress of the kingdom. The beauty and accomplishments of the young queen, Catharine de' Medici, could not prevail against her influence. The king delighted in giving public tokens of his infatuation, and not content with wearing her colors and blazoning

the palaces and public buildings with her emblems and devices, he admitted her to his councils, and in 1548 created her duchess of Valentinois. She retained her ascendency until Henry's death in 1559, when she retired to the palace built for her by her royal lover at Anet; but in 1561 she was recalled by Catharine de' Medici to exert her influence in detaching the constable de Montmorency from the Châtillons. From that time until her death she remained in retirement, retaining her personal charms, of which she had always taken the most extraordinary care, to the last. Her power over the king, even when she had reached the ripe age of 60, was due no less to her beauty than to her intellectual gifts. She seldom made a bad use of her position, and she spent large sums in charity.

DIAPASON (Gr. dia, through, and was, all), a term employed by the old Greek and Latin musicians to denote the scale or octave. Modern musicians sometimes employ it in a similar manner. The diapason stops of an organ are so called because they run through the whole register of the keyboard.

DIAPER, a linen fabric, said to have been originally made at Ypres in Belgium, and hence known as d'Ypres, whence its present name. It is distinguished by its flowered patterns, and sometimes resembles damask. It is largely manufactured for napkins, table-cloths, &c. Ireland, Germany, and Scotland especially produce excellent qualities of the article.

DIAPHORETICS, or SUDORIFICS (Gr. diape pew, to carry through), stimulant medicines, which increase the cutaneous transpiration. In this class were formerly included many substances, especially the mints and similar plants, which are only diaphoretic in virtue of the abundant, warm, and watery infusion in which they are administered. There are, however, certain substances, vegetable and mineral, which exert a special action upon the skin, stimu lating the sudoriferous glands, and eliminated by the cutaneous surface. Warm water is an excellent diaphoretic, either simple or in the form of the many domestic herb teas; the vapor and warm baths are effectual and natural stimulators of the skin; the cold bath, and the various applications of the hydrotherapie meth od, are sure but disagreeable and often dangerous sudorifics. Among vegetable remedies of this class are aconite, opium (alone or combined in the form of Dover's powder), dulcamara, guaiacum, sarsaparilla, mezereon, and squill. At the head of the mineral diaphoretics stand the antimonials; others are sulphur and the preparations of ammonia. The ethers, especially the nitrous, are powerfully diaphoretic when the surface is kept warmly covered. Indeed, many of the so-called diaphoretics, if the body be not kept warm, act as diuretics, increasing the urinary secretion; and almost any stimulating medicine will increase the secretion of the skin, if the surface be warmed or prevented from losing its heat by evaporation. Deficient action in the skin is seen in a great variety of complaints,

DIAPHRAGM

and in certain stages of almost all fevers, and the choice of the proper remedy to stimulate its action often requires the highest skill of the physician. Diaphoretics are employed to most advantage in chronic diseases of the skin, in gout and rheumatism, syphilis, dropsy, and catarrhal affections. When we consider the amount of carbonic acid and azotized matters thrown off by the skin, in its vicarious and alternating performance of the offices of the lungs and kidneys, we can understand how necessary it is to keep this surface in a healthy condition. The skin is a most important respiratory organ, and will keep up the standard of animal heat when the lungs are almost destroyed as aërating organs, giving a most valuable therapeutic indication in the treatment of pulmonary affections. According to Mr. Wilson, the total number of pores of the sudoriferous glands on the surface of the human body is about 7,000,000, and the length of the perspiratory tubing connected therewith nearly 28 miles. Such an extensive system as this cannot be neglected in disease with impunity, and the medicines which can stimulate it, when depressed or obstructed, must be among the most useful in the materia medica. It is highly probable that, in many forms of fever, the suppression of the perspiration is the cause of the disordered vascular action; and that deficient action of the cutaneous glandulæ, from want of exercise and inattention to cleanliness, is a frequent source of disease, from the accumulation in the blood of decomposing organic matter whose natural outlet is the skin. The cutaneous surface seems to be the natural channel for the elimination of many morbid products, and the use of diaphoretics to be the only rational method of removing such from the system. The experience of physicians in tropical climates shows that the great art of preserving health there consists in attention to the regular performance of the cutaneous functions, and that the adynamic fevers of those unhealthy regions are best treated by active diaphoretics.

DIAPHRAGM, the transverse muscle which separates the thoracic from the abdominal cavity in mammalian vertebrates. It is flattened in shape, nearly circular, fleshy at the edges, tendinous in the centre, elongated, and ending in a point behind. In front it is attached to the ensiform cartilage of the breast bone, on the sides to the posterior surface of the last 6 ribs, behind to the transverse process of the 1st lumbar vertebra and to the bodies of the first 3 vertebræ of the loins by tendinous slips; the fleshy fibres of the last form the pillars of the diaphragm, and their fasciculi cross each other in such a way as to leave 2 openings, one superior and most anterior, giving passage to the sophagus and par vagum nerve, the other inferior and more to the left, for the passage of the aorta, thoracic duct, and vena azygos; the tendinous centre has been compared to a leaf of clover. Between the middle and right portion of the tendinous centre is the opening for the

passage of the inferior vena cava. The diaphragm is in relation, above, with the pericardium in the middle, and with the pleuræ, base of the lungs, and walls of the chest on the sides; below, with the aorta in the middle, the kidneys, renal capsules, pancreas, and duodenum; on the right side with the liver, and on the left with the stomach and spleen. The direction of the posterior fibres is nearly vertical; all the others converge toward the tendinous centre. The diaphragm is the great muscle of respiration; when it contracts, its upward convexity becomes a plane surface, the cavity of the chest is enlarged, and air rushes in to expand the lungs during the act of inspiration; when forcibly contracted, it may act as an assistant to the abdominal expiratory muscles by diminishing the size of the base of the chest; by its action on the abdominal viscera it aids in the expulsion of fæces and urine; in ordinarily tranquil breathing the diaphragm is sufficient for the performance of the function. In animals the extent and position of the diaphragm vary according to the number of the ribs; in those whose ribs extend nearly to the pelvis, as in the horse, the thoracic convexity of the diaphragm is much greater than in man. This important muscle is liable to malformations, wounds, and morbid conditions; its total absence is incompatible with any other than intrauterine life, as aërial respiration would be impossible; its partial absence, like dilatation of its natural openings, or laceration of its fibres, is accompanied by the passage of more or less of the abdominal viscera into the chest, impeding the action of the heart, lungs, and digestive organs; in such cases, the liver, stomach, omentum, ileum, cæcum, and part of the colon, have been found above the diaphragm. This partition is also liable to penetrating wounds, and to rupture from external violence, the latter being the most dangerous; in either case, nature alone can remedy the evil. It is sometimes inflamed, and in the rheumatic diathesis is the seat of the most acute pain, increased by every respiratory act, and forcing the patient to breathe almost entirely by means of the abdominal muscles. Spasmodic contractions are familiarly known by the phenomenon of hiccough; this is sometimes merely a nervous affection, and at others is a symptom of peritonitis, strangulated hernia, and other abdominal diseases. Paralysis of the diaphragm is speedily fatal, from the suspension of respiration.

DIARBEKIR, DIYAR-BEKR, or DIARBEKR, a town of Turkey in Asia, formerly capital of an ancient pashalic of the same name, on a rocky eminence a short distance from the right bank of the river Tigris, in lat. 37° 55′ 30′′ N., long. 39° 52' E. A fertile and well cultivated plain surrounds the city, which is encompassed by walls pierced by 4 gates, and surmounted by many towers. In the N. E. portion of the town are the ruins of the citadel, formerly the residence of the pasha. The town was once a very flourishing place, and contained, it is said, 200,