Page:The American Cyclopædia (1879) Volume XV.djvu/790

 760 TIN (mosaic gold, tho aurum musivum or mosai- cum of the alchemists). A mixture of stannous and stannic chloride, added to gold chloride in solution, precipitates a purple powder, sup- posed to be stannic oxide, colored by metallic gold in fine particles, or a mixture or combi- nation of the oxides of gold and tin. It is known as the purple of Cassius, and is used for coloring porcelain and glass, with which it is incorporated by fusion. The amalgam of tin and its alloys with lead and other metals is employed in the arts. (See AMALGAM, BRITANNIA METAL, BRONZE, MIRROR, PEWTER, and SPECULUM.) History. Tin ore, being a heavy mineral, not altered by ordinary mete- oric agencies, may occur in alluvial and diluvial deposits, like gold and precious stones ; and being also, when pure, easily reduced by smelt- ing, its treatment might naturally become known to nations of great antiquity. It is often said that the Hebrews, Egyptians, and Greeks employed this metal ; but so far as the question turns upon the Hebrew bedil (Ezek. xxvii. 12 ; Numb. xxxi. 22 ; Isa. i. 25, &c.) and the Greek naooirepos, which have been trans- lated as tin, this seems doubtful. Tin was certainly often confounded with lead, being called by the Romans plumbum candidum. Even the stannum of Pliny was not tin ; and not until the 4th century does stannum definite- ly bear this meaning. (See Kopp's Geschichte der Chemie.) But bronze vessels found at Thebes are said to be in part composed of tin, which Wilkinson suggests the Egyptians may have obtained from Spain or India long before the Phoenicians voyaged in the Atlantic. The latter people brought Kaaotrepoq from the Cas- siterides, supposed to have been the Scilly islands, off the coast of Britain. This may have been brought to the Scilly islands from Cornwall, or else, it is presumed, the Phoeni- cians pretended to visit these islands, and gave them a deceptive name, in order to mislead the Romans and conceal their real trade on the Cornish coast. (See "Transac- tions of the Geological Society of Cornwall," vols. iii. and iv.) Spain also is believed to have furnished tin to the Phoenicians. In the middle ages Cornish tin was used for church bells, and later for bronze cannon. The an- cient Mexicans obtained tin from the mines of Tasco, and with it made bronze for very hard cutting tools ; and they used small T-shaped pieces of tin for money. Cortes had bronze cannon made with the tin of Tasco. Distri- bution. Native metallic tin is one of the rarest of minerals. It has been reported from Sibe- ria, Bolivia (doubtful), and Pennsylvania. (See Genth's recent volume on the mineralogy of that state.) There is a native sulphide (stan- nine, tin pyrites), but the only ore com- mercially utilized is the stannic oxide, called tinstone or stannite, Sn0 2 ; sp. gr. 6 - 94; crys- talline form, tetragonal pyramids ; percentage of tin, 78-38 ; crystals yellowish and translu- cent when pure, but usually dark brown, al- most black, from admixture of ferric and man- ganic oxide. This occurs in veins, beds, and Stockwerke, or in secondary (alluvial and di- luvial) deposits. In the former case, it is found in quartzose crystalline rocks (granite, gneiss, porphyry, mica and hornblende schists, quartz-porphyry, &c.), associated with arseni- cal pyrites, iron and copper pyrites, bismuth, zinc blende, wolfram, molybdenite, specular iron, &c., and with such earthy minerals as feldspar, tourmaline, chlorite, topaz, apatite, fluor spar, and scheelite. The leading locali- ties where such deposits have been worked are Cornwall and the Saxon and Bohemian Erzgebirge. Tin veins also occur in Brittany, Finland, Spain, Mexico, Bolivia, and New South Wales. The placer deposits are illus- trated at the islands of Banca and Billiton in the Malay peninsula, and at some otlier points in the East Indies. The tin placers of Aus- tralia have also furnished of late large quanti- ties of tin ore ; and such deposits (stream tin) occur subordinately in Cornwall, Brittany, Spain, and elsewhere. A remarkable deposit of tin ore in a dike of trachyte is said to exist in Durango, Mexico. Stannite occurs with cryolite in Greenland. Tin ore in veins, dikes, or beds of dark porphyry is found in San Bernardino county, southern California ; spe- cimens are said to have been found in Idaho, in the bed of a stream ; and several localities in the Appalachian regions are known to min- eralogists as furnishing the ore in occasional crystals or in thin veins. Chesterfield and Goshen, ^lass., and Lyme and Jackson, N. H., are localities of stannite ; and tin has been de- tected in the magnetic iron ore of the highlands of New York and New Jersey, and in some of the auriferous ores of Virginia. The tin- ore deposits of Missouri, the object of a con- siderable speculative excitement a few years ago, seem to consist in the replacement to a minute extent, in certain crystalline schists, of titanic by stannic acid, the two being iso- morphous. The relative importance of the chief tin-producing regions is shown by the following estimates of production in tons : REGIONS OF PRODUCTION. 1872. 1873. 1874. United Kingdom 9560 9970 10000 8203 4 3V> 4 049 Billiton. . 2.946 2 y$o 3 157 Malacca 9785 ')( 7149 Australia 150 2990 5800 The amount credited to Great Britain includes the tin produced in that country from import- ed Australian ores. The product of Bolivia or Upper Peru, known as Peruvian tin, was esti- mated in 1868 by English authorities at 1,500 tons ; but it is probably much less at present, since no account is taken of it in the trade reports. Saxony and Bohemia produce an in- significant quantity, not more than 200 or 300 tons in all ; and Spain yields still less. In the tin mines of Cornwall the ore occurs in small