ME NACH A NITE

an ore of titanium , found in the bed of a rivulet which flows into the valley Men a can, in Cornwall. MERCURY or QUICKSILVER. This metal is distinguished by its fluidity at common temperatures; its density = 13·6; its silver blue lustre; and its extreme mobility. A cold of 39° below zero of Fahrenheit, or -40° cent., is required for its congelation, in which state its density is increased in the proportion of 10 to 9, or it becomes of spec. grav. 15·0. At a temperature of 656° F. it boils and distils off in an elastic vapour; which, being condensed by cold, forms purified mercury. Mercury combines with great readine with certain metals, as gold, silver, zinc, tin, and bismuth, forming, in certain proportions, fluid solutions of these metals. Such mercurial alloys are called amalgams . This property is extensively employed in many arts; as in extracting gold and silver from their ores; in gilding, plating, making looking-gla es, . Humboldt estimates at 16,000 quintals, of 100 lbs. each, the quantity of mercury annually employed at his visit to America, in the treatment of the mines of New Spain; three-fourths of which came from European mines. The mercurial ores may be divided into four species :— 1. Native quicksilver. —It occurs in most of the mines of the other mercurial ores, in the form of small drops attached to the rocks, or lodged in the crevices of other ores. 2. Argental mercury, or native silver amalgam. —It has a silver-white colour, and is more or le soft, according to the proportion which the mercury bears to the silver. Its density is sometimes so high as 14. A moderate heat di ipates the mercury, and leaves the silver. Klaproth states its constituents at silver 36, and mercury 64, in 100; but Cordier makes them to be, 27 1 ⁄ 2 silver, and 72 1 ⁄ 2 mercury. It occurs crystallized in a variety of forms. It has been found in the territory of Deux-Ponts, at Rozenau and Niderstana, in Hungary, in a canton of Tyrol, at Sahlberg in Sweden, at Kolyvan in Siberia, and at Allémont in Dauphiny; in small quantity at Almaden in Spain, and at Idria in Carniola. By the chemical union of the mercury with the silver, the amalgam, which should by calculation have a spec. grav. of only 12·5, acquires that of 14·11, according to M. Cordier. 3. Sulphuret of mercury , commonly called Cinnabar, is a red mineral of various shades; burning at the blowpipe with a blue flame, volatilizing entirely with the smell of burning sulphur, and giving a quicksilver coating to a plate of copper held in the fumes. Even the powder of cinnabar rubbed on copper whitens it. Its density varies from 6·9 to 10·2. It becomes negatively electrical by friction. Analysed by Klaproth, it was found to consist of mercury 84·5, sulphur 14·75. Its composition, viewed as a bisulphuret of mercury, is, mercury 86·2, sulphur 13·8. The finest crystals of sulphuret of mercury come from China, and Almaden in Spain. These contain, according to Klaproth, 85 per cent. of mercury. A bituminous sulphuret of mercury appears to be the base of the great exploration of Idria; it is of a dark liver-red hue; and of a slaty texture, with straight or twisted plates. It exists in large ma es in the bituminous schists of Idria. M. Beurard mentions also the locality of Munster-Appel, in the duchy of Deux-Ponts, where the ore includes impre ions of fishes, curiously spotted with cinnabar. The compact variety of the Idria ore seems very complex in composition, according to the following analysis of Klaproth:—Mercury, 81·8; sulphur, 13·75; carbon, 2·3; silica, 0·65; alumina, 0·55; oxide of iron, 0·20; copper, 0·02; water, 0·73; in 100 parts. M. Beurard mentions another variety from the Palatinate, which yields a large quantity of bitumen by distillation; and it was present in all the specimens of these ores analyzed by me for the German Mines Company. At Idria and Almaden the sulphurets are extremely rich in mercury. 4. Muriated mercury , or the Chloride of mercury , commonly called Horn mercury. This ore occurs in very small crystals of a pearl-gray or greenish-gray colour, or in small nipples which stud, like crystals, the cavities, fi ures, or geodes among the ferruginous gangues of the other ores of mercury. It is brittle, and entirely volatile at the blowpipe, characters which distinguish it from horn silver. The geological position of the mercurial ores, in all parts of the world, is in the strata which commence the series of secondary formations. Sometimes they are found in the red sandstone above the coal, as at Menildot, in the old dutchy of Deux-Ponts, at Durasno in Mexico, at Cuença in New Granada, at Cerros de Gauzan and Upar in Peru; in the subordinate porphyries, as at Deux-Ponts, San Juan de la Chica in Peru, and at Cerro-del-Fraile, near the town of San-Felipe, they occur also among the strata below, or subordinate to the calcareous formation, called zechstein , in Germany, or among the accompanying bituminous schists, as at Idria in Carniola; and, lastly, they form ma es in the zechstein itself. Thus, it appears that the mercurial deposits are confined within very narrow geological limits, between the calcareous beds of zechstein, and the red sandstone. They occur at times in carbonaceous nodules, derived from the decomposition of mo es of various kinds; and the whole mercurial deposit is occasionally covered with beds of charcoal, as at Durasno. They are even sometimes accompanied with the remains of organic bodies, such as casts of fishes, fo il shells, silicified wood, and true coal. The last fact has been observed at Potzberg, in the works of Drey-Koenigszug, by M. Brongniart. These sandstones, bituminous schists, and indurated clays, contain mercury both in the state of sulphuret and in the native form. They are more or le penetrated with the ore, forming sometimes numerous beds of very great thickne ; while, in the more antient or the primitive formations, these ores exist only in very small quantity a ociated with tin. Mercury is, generally speaking, a metal sparingly distributed in nature, and its mines are very rare. The great exploitations of Idria in Friuli, in the county of Goritz, were discovered in 1497, and the principal ore mined there is the bituminous sulphuret. The workings of this mine have been pushed to the depth of 280 yards. The product in quicksilver might easily amount annually to 6000 metric quintals = 600 tons British; but, in order to uphold the price of the metal, the Austrian government has restricted the production to 150 tons. The memorable fire of 1803 was most disastrous to these mines. It was extinguished only by drowning all the underground workings. The sublimed mercury in this catastrophe occasioned diseases and nervous tremblings to more than 900 persons in the neighbourhood. Pliny has recorded two interesting facts: 1. that the Greeks imported red cinnabar from Almaden 700 years before the Christian era; and 2. that Rome, in his time, annually received 700,000 pounds from the same mines. Since 1827, they have produced 22,000 cwts. of mercury every year, with a corps of 700 miners and 200 smelters; and, indeed, the veins are so extremely rich, that though they have been worked pretty constantly during so many centuries, the mines have hardly reached the depth of 330 yards, or something le than 1000 feet. The lode actually under exploration is from 14 to 16 yards thick, and it becomes thicker still at the cro ing of the veins. The totality of the ore is extracted. It yields in their smelting works only 10 per cent. upon an average, but there is no doubt, from the analysis of the ores, that nearly one half of the quicksilver is lost, and dispersed in the air, to the great injury of the workmen’s health, in consequence of the barbarous apparatus of aludels employed in its sublimation; an apparatus which has remained without any material change for the better since the days of the Moorish dominion in Spain. M. Le Play, the eminent In gen i eur des Mines , who published, in a recent volume of the Annales des Mines, his Itinéraire to Almaden, says, that the mercurial contents of the ores are not able ment plus elevées than the product. These veins extend all the way from the town of Chillon to Almadenejos. Upon the borders of the streamlet Balde Azogues, a black slate is also mined which is abundantly impregnated with metallic mercury. The ores are treated in 13 double furnaces, which I shall presently describe. “Le mercure,” says M. Le Play, “a sur la santé des ouvriers la plus funeste influence, et l’on ne peut se défendre d’un sentiment pénible en voyant l’empre ement avec lequel des jeunes gens, pleins de force et de santé, se disputent la faveur d’aller chercher dans les mines, des maladies cruelles, et souvent une mort prématurée. La population des mineurs d’Almaden méritent le plus haut interêt.” These victims of a deplorable mismanagement are described as being a laborious, simple-minded, virtuous race of beings, who are thus condemned to breathe an atmosphere impregnated far and near with the fumes of a volatile poison, which the le ons of science, as I shall presently demonstrate, might readily repre , with the effect of not only protecting the health of the population, but of vastly augmenting the revenues of the state. These celebrated mines, near to which lie those of Las Cuebas and of Almadenejos , were known to the Romans. After having been the property of the religious knights of Calatrava , who had a isted in expelling the Moors, they were farmed off to the celebrated Fugger merchants of Augsbourg; and afterwards explored on account of the government, from the date of 1645 till the present time. Their produce was, till very lately, entirely appropriated to the treatment of the gold and silver ores of the new world. The mines of the Palatinate , situated on the left bank of the Rhine, though they do not approach in richne and importance to those of Idria and Almaden, merit, however, all the attention of the government that farms them out. They are numerous, and varied in geological position. Those of Drey-Koenigszug, at Potzberg, near Ku el, deserve particular notice. The workings have reached a depth of more than 220 yards; the ore being a sandstone strongly impregnated with sulphuret of mercury. The produce of these mines is estimated at about 30 tons per annum. There are also in Hungary, Bohemia, and several other parts of Germany, some inconsiderable exploitations of mercury, the total produce of which is valued at about 30 or 40 tons on an average of several years. The mines of Guancavelica, in Peru, are the more interesting, as their products are directly employed in treating the ores of gold and silver, which abound in that portion of America. These quicksilver mines, explored since 1570, produced, up to 1800, 53,700 tons of that metal; but the actual produce of the explorations of these countries was, according to Helms, about the beginning of this century, from 170 to 180 tons per annum. In 1782 recourse was had by the South American miners to the mercury extracted in the province of Yun-nan, in China. The metallurgic treatment of the quicksilver ores is tolerably simple. In general, when the sulphuret of mercury, the most common ore, has been pulverized, and sometimes washed, it is introduced into retorts of cast iron, sheet iron, or even stoneware, in mixture with an equal weight of quicklime. These retorts are arranged in various ways. Prior to the 17th century, the method called per descensum was the only one in use for distilling mercury; and it was effected by means of two earthen pots adjusted over each other. The upper pot, filled with ore, and closed at the top, was covered over with burning fuel; and the mercurial vapours expelled by the heat, pa ed down through small holes in the bottom of the pot, to be condensed in another ve el placed below. However convenient this apparatus might be, on account of the facility of transporting it, wherever the ore was found, its inefficiency and the lo es it occasioned were eventually recognized. Hence, before 1635, some smelting works of the Palatinate had given up the method per descensum , which was, however, still retained in Idria; and they substituted for it the furnaces called galleries . At first earthenware retorts were employed in these furnaces; but they were soon succeeded by iron retorts. In the Palatinate this mode of operating is still in use. At Idria, in the year 1750, a great distillatory apparatus was established for the treatment of the mercurial ores, in imitation of those which previously existed at Almaden, in Spain, and called aludel-furnaces . But, since 1794, these aludels have been suppre ed, and new distillatory apparatus have been constructed at Idria, remarkable only for their magnitude; exceeding, in this respect, every other metallurgic erection. There exist, therefore, three kinds of apparatus for the distillation of mercury: 1. the furnace called a gallery ; 2. the furnace with aludels ; and 3. the large apparatus of Idria. I shall describe each of these briefly, in succe ion. IMG:4147767755307473660_illo0805.png:Gallery of the Palatinate furnace 1. Furnace called Gallery of the Palatinate. —The construction of this furnace is disposed so as to contain four ranges, a a′ , b b′ , of large retorts, styled cucurbits, of cast iron, in which the ore of mercury is subjected to distillation. This arrangement is shewn in fig. 656. , which presents a vertical section in the line a b of the ground plan, fig. 657. In the ground plan, the roof e e′ of the furnace ( fig. 656. ) is supposed to be lifted off, in order to shew the disposition of the four ranges of cucurbits upon the grate c f , figs. 656 , 657. , which receives the pit-coal employed as fuel. Under this grate extends an ash-pit d . Fig. 658. , which exhibits an elevation of the furnace, points out this ash-pit, as well as one of the two doors c , by which the fuel is thrown upon the grate c f . Openings e e , ( fig. 656. ) are left over the top arch of the furnace, whereby the draught of air may receive a suitable direction. The grate of the fire-place extends over the whole length of the furnace, fig. 657. , from the door c to the door f , situated at the opposite extremity. The furnace called gallery includes commonly 30 cucurbits, and in some establishments even 52. Into each are introduced from 56 to 70 pounds of ore, and 15 to 18 pounds of quicklime, a mixture which fills no more than two-thirds of the cucurbit; to the neck a stoneware receiver is adapted, containing water to half its height. The fire, at first moderate, is eventually pushed till the cucurbits are red hot. The operation being concluded, the contents of the receivers are poured out into a wooden bowl placed upon a plank above a bucket; the quicksilver falls to the bottom of the bowl, and the water draws over the black mercury , for so the substance that coats the inside of the receivers is called. This is considered to be a mixture of sulphuret and oxide of mercury. The black mercury , taken out of the tub and dried, is distilled anew with exce of lime; after which the residuum in the retorts is thrown away, as usele . IMG:4147767755307473660_illo0806a.png:Aludel furnace Figs. 659 and 660 enlarged (180 kB)