Mercury, Or Inicksilver, a metal of the coloor and lustre of silver, and fluid at ordinary temperatures, whence its ancient name of ar-aentnm ttrum, and that by which it was called by Aristotle and Theophrastus, who made the earliest mention of it,Mercury Or Inicksilver 1100201 , fluid silver, It was also known as hydrargyrum, and from this its chemical symbol, Hg, is derived. The equivalent of the metal is 200; and its specific gravity, which varies somewhat with the temperature, is -riven by Kopp as 13557 at 62-0° F. At 39o or 40° below zero F. the metal becomes solid and crystallizes in Tegular octahedrons, contracting in bulk and assuming the density of 14; the mass is malleable, and resembles lead. Its boiling point is 662° F. at which it forms an invisible, transparent vapor, the density of which is 6,970, air being 1,000. Before assuming this form, if exposed to the air at high temperatures, it absorbs oxygen and is converted into the red oxide, which is decomposed at the boiling point. Above 40° F. mercury is somewhat volatile, as may be shown by holding an iodized daguerreotype plate, that has been submitted to the action of light in the camera, over a bath of mercury, when the picture will be brought out by the vapor. Gold leaf is also affected by the vapor when suspended in a vial containing mercury and kept at ordinary temperatures. Strong nitric acid dissolves mercury; but hydrochloric acid, hot or cold, does not affect it.

It is oxidized by heated concentrated sulphuric acid, and is soluble in a solution of common salt. Exposed for a long time to the air, mercury gathers a film of gray oxide upon its surface, which adheres to the glass in which the metal is contained; glycerine is employed to prevent the formation of this film. When mercury contains dissolved in it lead, zinc, or other extraneous oxidizable metals, these may be removed by covering the surface of the metal, placed in a shallow vessel, with dilute nitric acid, and stirring frequently. The acid attacks and takes up the foreign matters, and may also form a crust of nitrate with a small portion of the mercury. This is a more efficient method of purification than that of distillation when zinc is present, as this is distilled over with the mercury. Impurities mechanically mixed with mercury may often be removed by straining the metal through paper perforated with a very small hole, or squeezing it through wash leather. But if a film of oxide still adheres to the mercury, this may be removed by agitating it violently in a bottle in which some powdered white sugar has been introduced, then blowing air into the bottle, repeating the shaking and blowing several times, and then filtering.

Mercury unites with various metals, as gold, silver, tin, lead, zinc, and bismuth, forming compounds which are noticed under the head of Amalgam. In some cases the cheapest of the metals named have been used to adulterate mercury. The effect of this mixture is to produce an amalgam, the presence of which is easily detected by the fluid, when poured upon a plate of glass or porcelain, not flowing freely, but leaving a trace behind it. - Mercury occurs native in globules scattered through masses of rocks or ore, and also (rarely) in the form of a silver amalgam; but chiefly as a sulphide of mercury. (See Cinnabau.) It seldom if ever occurs in fissure veins, though sometimes it impregnates or constitutes well defined deposits. It is found in geological formations of almost all ages, and particularly in talcose and argillaceous slates. The most important deposit in the world is that of Almaden in Spain, from which, according to Pliny, the Romans annually obtained about 700,000 lbs. of cinnabar. The matrix of the ore consists of quartz and quartz-oso sandstone, intermixed with cinnabar in beds or intercalated veins, enclosed in slates and quartzites of upper Silurian age. A mass of ore nearly 100 ft. wide, called el Bosario, constitutes the largest development.

The Spanish government holds the title and has leased the mines to the Rothschilds. The average yield of all the ore is about 7.85 per cent. (See Almaden.) The annual production of the Spanish mines was estimated in 1867 at about 2,500,000 lbs. At Idria, in Illyria, cinnabar occurs impregnating beds of limestone of uncertain age. (See Idria.) These mines are controlled by the government, and the product in 1871 was 750,400 lbs., and about 123,200 lbs. of artificial cinnabar. The material is very soft, sometimes contains globules of mercury, and gives off mercurial fumes which injure the health of the workmen. In the Palatinate quicksilver ores are found at moderate depths distributed in the fissures of the rock apparently by sublimation. At Ripa, in Modena, cinnabar impregnates micaceous and talcose slates. At Vail' Alta, in Venetia, it occurs in the calcareous schists and in quartz-ose porphyry. Native mercury is found at Montpellier in France, disseminated through tertiary marls and calcareous conglomerate. In Chili cinnabar is found in granitic rocks, and in Peru in sandstone associated with coal.

The great Peruvian mines of Huancavelica were worked as early as 1506. The product down to 1845 was about 1,100,000 quintals of mercury (101.60 lbs. each). Of this only 66,000 quintals were produced after 1789, up to which time Humboldt gives the production as 1,040,-469 quintals, worth at the government price $75,954,237. The present annual production of Feru probably does not exceed 200,000 lbs. Mercury is found at many localities in Mexico, but is not extracted at present on a large scale. The great consumption of this metal in the patio process at the haciendas or metallurgical works of Mexico is supplied by importations from Spain and California. - The deposits of New Almaden, 12 m. from San Jose, in Santa Clara co., California, occur in the Coast range, in a belt of altered cretaceous slates, between beds of serpentine on either side. The ore is found in a series of irregular cavities occurring without apparent connection or order. The average yield of the ore worked in 1873 at New Almaden was 7.86 per cent, quicksilver; a large amount (something more than one half) of the material reduced in that year was tierras or poor earthy screenings, yielding 2 per cent. This reduced the general average to 4.87 per cent.

The product of this property for 21 1/4 years, ending Dec. 31, 1873, was as follows:

New Almaden mine...

578,160

flasks,

or 48.845.976 lbs.

Enriquita "...

10,571

"

or 808,681 "

Total................

688,721

flasks,

or 44,654,056 lbs.

(A flask contains 76 1/2 lbs.) The deposit at New Almaden was first found by Indians, who used the material as a paint, and excavated openings 50 or GO ft. into the mountain in search of it.

In 1824 and afterward the Spaniards attempted to work it for silver. In 1845 it was worked first for mercury by Capt. Castillero. Operations were suspended during the war, and recommenced in 1848, and a company of Mexicans and English held the mine from 1850 to 1858, when they were enjoined, pending litigation as to title. The value of the product up to this time had amounted, according to legal papers, to over $8,000,000, and was estimated at $1,000,000 annually. The total value of the New Almaden property was rated by the United States attorney general at $15,000,-000. In the same neighborhood the Enri-quita, Providencia, and Guadalupe mines have been worked. In Fresno county the New Idria series of mines, including the San Carlos, Aurora, Idria, Molino, Washington, Benada, and Victorener mines, contain cinnabar in sandstone and slate. The Panoche Grande, in this county, is famous in the records of litigation and legislation as the McGarrahan claim. The Redington mine in Lake county is similar in formation to the New Almaden. The decrease of late years in the production of quicksilver in California, and the consequent rise in price, have led to numerous discoveries and new openings of mines in that state.

The producing mines in 1873 are given as follows: New Almaden, 11,042 flasks; New Idria, 7,600; Redington, 4,200; Great Western, 651; Manhattan, 621; Summit, 75; American, 128; Napa, 199; California, 995; Phoenix, 880; Washington, 197. As the price of quicksilver had risen by the end of the year to $1 20 per pound, and had averaged during the year something over $1 per pound, the product of California in 1873 may be valued at more than $2,000,000. In quantity the production was less than that of previous years. California yielded in 1867, according to the reports of the Paris exposition, 3,960,000 lbs., out of a total for all countries of 7,083,120 lbs. - The methods employed in mining quicksilver ores present no peculiar features, except those which are incident to the great irregularity of the deposits. The theory of the reduction of the ores is simple. Pure cinnabar contains 13.79 parts of sulphur to 86.21 of quicksilver. The general average of the ores extracted is, however, less than 10 per cent, of quicksilver; in the majority of the deposits in California not over 2 per cent. Even much poorer ore than this is worked in other parts of the world. The difference in the grade of ore depends upon the proportion of intermixed gangue or sterile rock.

The cinnabar itself is usually nearly pure. In treating it, the sulphur must first be separated from the quicksilver, and then, since in this process the quicksilver is vaporized, its metallic fumes must be recondensed. Two systems are cm-ployed. By the first the powdered ore is heated in retorts with 50 per cent, of its weight of lime or iron filings. The sulphur combines with the lime or iron, forming a non-volatile sulphide, setting free the mercury, the fumes of which are then passed into condensers. By the second system the ore is burned in furnaces, where the sulphur is converted into sulphurous acid gas by the admission of air, and the quicksilver is set free as a vapor. All the vapors and gases from this combustion pass into condensing chambers, where the quicksilver is condensed, while the gases escape to the chimney. The retort system, although less wasteful in quicksilver, involves so much additional expense that it is not advantageous in practice. The roasting of cinnabar in furnaces is now universal. The furnaces used are of two general classes, intermittent and perpetual. In the former, a large charge is introduced, burned, and withdrawn when it has become cool, leaving the furnace ready for another.

In a perpetual furnace small charges are continually introduced at stated intervals, and the burned ore is withdrawn without interrupting the process. Intermittent furnaces of different varieties are used at Almaden, Idria, and some points in California. A Spanish furnace at Almaden is peculiar in its system of condensation, by which the quicksilver is distilled in large numbers of clay crucibles joined together like pipes. The conden-ing chambers contain 528 of these in 12 rows of 44 each. Each Aludel, so called, is about 18 in. long, 10 in. wide in the middle, and 6 in. wide at each end, where it fits into the next. A small hole in each allows the condensed quicksilver to how out into a gutter leading to a central channel. The furnace consists of a cylindrical shaft about 6 ft. in diameter and 25 ft. high, divided by perforated arches, 9 or 10 ft. from the top, into two compartments, the upper being for ore and the lower for fuel. The process of burning and distilling quicksilver lasts three days. On the fourth (lay the furnace is recharged, and the Aludeln are taken up, emptied, and rearranged. The furnace used at Idria has a series of brick chambers separated by partition walls for condensing the quicksilver. The intermittent furnaces of California are also provided with brick condensers.

The power which bricks have of retaining heat is one of the greatest objections to their use; another is the inevitable loss of quicksilver, which forces its way even through the best made bottoms of condensing chambers and through imperceptible cracks in the walls. The furnaces of California are built upon arches, and near the bottom of these arches pieces of sheet iron are placed in the masonry, which catch the quicksilver as it biters through, and conduct it to a basin. The merit of brick condensers as compared with iron lies in their ease of construction and re-piir, and in their indifference to the sulphuric acid which is formed with the sulphurous acid gases in contact with steam and oxygen. The intermittent furnaces at New Almaden are 40 ft. ong 8 ft. wide, and 10 ft. high, each being divided into compartments, the tiro occupying one at the end, and the heat passing through the ores into flues. A charge of 15,000 lbs. is worked in 60 hours with wood fuel. A flue from the furnace passes upward to the first condensation chamber, which is 8 ft. long, 4 ft. broad, and 5 ft. high. The chambers are covered with cast-iron plates luted down.

After passing through eight chambers the remaining vapors are conducted into a tank, where they are sprinkled with water, and thence escape by wooden chimneys. The ore is usually so mixed for treatment as to present a uniform low percentage. The finer fragments are worked up with the soft loamy portion, and the mass is kneaded with water and moulded into bricks, which being dried in the sun are worked like the rest. A great saving of fuel may be effected by the use of perpetual furnaces, or of kilns such as are employed for roasting iron ore or lime. Of this class are the Albert! furnace, which is a reverberatory, and hence suitable for small-sized pieces only; the Halmer, Pult, and Vail' Alta, which are shaft furnaces employed in Europe; and the furnaces of Riotte, Knox, and Pershbacker, which are California improvements. Cast-iron, wooden, or wooden and sheet-iron tanks, or iron tubes, are employed as condensers. Draft is obtained by means of suction fans. From 20 to 24 tons of ore is passed through a perpetual furnace daily, every ton remaining in the furnace nine hours above the fire bridge, and an additional time of three to four hours below the fire bridge in the hottest portion of the furnace, where the last particles of quicksilver are expelled.

The great subtilty with which the vapors of this metal penetrate through the minutest openings is well known to workmen at quicksilver furnaces. Beneath the old furnaces at New Almaden 2,000 flasks were recovered by washing out the ground to a depth of 30 ft. The men and animals employed about the smelting works are subject to salivation and other injurious effects; and the same is true of mines where, as at Idria, native mercury occurs in the ores, and the atmosphere is contaminated with mercurial fumes. At New Almaden there has been little or no complaint among the miners. - Metallic mercury in its usual form has no action upon the human system; it has been taken with impunity in quantities of a pound weight; but in vapor it acts energetically, producing its constitutional effects. Poisoning occasionally results from exposure to the vapor of mercury, as from the breaking of packages in the hold of a ship, or in various processes in the arts, as in gilding, in silvering mirrors, etc. Mercury is used in medicine in many forms, all of which may give rise to its constitutional effects, varying in the time required for the production of their action and in the nature of the local disturbance they produce.

Mercury with chalk, or hydrargyrum cum creta, prepared by rubbing up 3 oz. of mercury with 5 oz. of prepared chalk, and blue pill made from a mass composed of 1 oz. of mercury rubbed up with 1 1/2 oz. of confection of roses, and then beaten with 1/2 oz. of powdered liquorice root, are preparations in very frequent use. The metal should be contained in them in a state of division so tine that its globules are not made visible by a lens magnifying four diameters or more. A small portion of oxide is probably present in them also, which is more soluble than metallic mercury, and thus renders the preparations more active. When blue pill is taken in small but repeated doses, the first appreciable effect is usually an increased activity of the secretions, particularly of the intestinal canal, the discharges from which become liquid and bilious; the mucous membrane of the lungs and genitourinary apparatus may display a similarly augmented secretion. If there happen to be anywhere an interstitial deposit of tibrine, or an exudation of lymph, or effusion of serum, its absorption may now be promoted; although Stille says if the mercurial influence be carried too far, extensive ulcers will appear, sometimes coated with false membranes or exudations, and the eyelids and ankles may become cede-matous, and even general dropsy may ensue.

In the next grade of the unfavorable action of mercury the appetite fails, digestion is impaired, the secretions become still thinner and more copious, the firmness of the tissues diminishes, newly formed callus is dissolved, and recently healed wounds open afresh; the muscles waste, the skin has an earthy paleness, with the other consequences mentioned above. These symptoms, says Stille, appear to depend upon the radical change which the blood has undergone by losing a large portion of its natural solid constituents, and perhaps a formation of less highly vitalized compounds of albumen with the mercurial salt. Salivation is one of the most ordinary effects of the continued use of mercury, and consists in a copious flow of watery saliva, accompanied with swelling and soreness of the gums and a peculiar fetor of the breath. Ulcerations of the mouth may occur. The power of mercury to increase the secretion or discharge of bile, which for many years has been one of the most undoubted articles of medical faith, has recently been called in question; but although it can be shown clearly enough that in certain dogs the secretion of bile is not increased thereby, yet there seems to be not only clinical but experimental evidence to show that, in some way or other, the flow of bile into the intestine is rendered more copious by mercurial action.

The constitutional action of most of the other mercurial preparations resembles that first described. Calomel (technically called hydrargyri chloridum mite) is often given as a cathartic, and when so given produces no constitutional action whatever, except in persons who are endowed with a peculiar and exceptional sensitiveness to its action. Corrosive sublimate is an irritant poison even in quite small doses, but when given in doses of 1/20 to 1/12 of a grain it is one of the best forms in which to use the drug for its systemic action. Turpeth mineral, which is a basic sulphate, is used as an emetic, and only exceptionally is absorbed in sufficient quantity to produce constitutional effects. Inunctions with mercurial ointment and fumigations with the bisulphuret or other salts may also introduce the metal into the system and give rise to the effects above described. Both calomel and corrosive sublimate have been injected subcutaneously, but when administered in this way are liable to produce abscesses. Mercurial fever and mercurial tremors, the latter often an extremely obstinate affection, are among the constitutional effects of mercury.

Stille says: "Few medicines produce such a marked sense of depression, both mental and bodily, as mercury even in ordinary doses; but when the system is brought thoroughly under its influence, these effects become distressing; the susceptibility to external impressions, and particularly to that of cold, is augmented, pains in the limbs are felt, slight annoyances disturb the equanimity, and sometimes mental debility ensues, so that a moody melancholy and fear of death may overtake the patient." The statements in regard to the resemblance of lesions induced by mercury to those of the later stages of syphilis are probably exaggerated, as the symptoms of mercurial poisoning, however severe they may be, are not, so far as can be ascertained by examining workmen in establishments where mercury is used and mercurial poisoning familiar, the same as those of syphilis. - It is impossible to give in any reasonable space an account of the uses which have been made of mercury in various diseases. It is much less used now than formerly, and its marked constitutional effects when it is employed are avoided, if possible, rather than sought for.

It is most largely employed in the treatment of syphilis, but it can be shown that even here it is not absolutely essential, although surgeons of great experience are confident that the disease is rendered shorter and more manageable thereby. The general verdict of the medical profession is undoubtedly in favor of using mercury in the treatment of syphilitic disease, but of limiting its use to appropriate cases. It should not be administered indiscriminately in syphilitic any more than in other affections. In tertiary syphilis it should be used with great caution, if at all. It is given most advantngeously in the primary, secondary, and hereditary forms of the disease, when these occur in individuals whose constitutions are capable of bearing the action of the drug. Whenever inflammation, especially of serous membranes, is accompanied with exudation, the careful administration of mercury is often of advantage in promoting absorption of the exudation. - Mercury is a diad, and forms two sets of compounds, the mercurous and mercuric salts; there are two oxides, mercury monoxide or mercuric oxide, HgO, and mercurous oxide, Hg20. When mercuric oxide is prepared by decomposing the nitrate by heat, it has a bright orange color, and is known as the rod oxide of mercury.

In the state of a finely levigated powder, or as an ointment, this is applied externally in medicine as a stimulant and caustic. The name red precipitate, or precipitate perse, was given to this oxide because of the manner in which it was formerly prepared. Mercury in a matrass (a glass vessel with a long narrow neck) was ojected continuously to the action of heat. The mercurial vapor rising in the neck of the matrass was converted into red oxide, which was prevented from escaping; and as the operation went on for weeks, the whole was converted into the same compound. Other mercurial compounds of especial interest are the subchloride and chloride, the one described under Calomel and the other under Cokko-sive Sublimate. - In the arts, mercury is employed in the construction of philosophical in-struments, and is preferred to other fluids for filling thermometers and barometers by reason of the great range of temperature through which it expands or contracts uniformly with equal increase or decrease of heat. Its amalgam with tin is largely used for coating or "silvering" the hacks of mirrors. The paint, vermilion, is its sulphuret, cinnabar.

But its principal consumption is in the extraction of silver and gold from their ores in the amalgamating process. (See Amalgamation).