'MICR SHAH, second son of Ahmad Shah, succeeded his father as Amir of Kabul in a.n. 1773, and died in 1793. He left 36 children, of whom 23 were sons.
TIN.
Tin is one of those metals which were earliest known. Though it occurs in comparatively few countries, and though it does not occur in the native state, the acquaintance of the ancients 4% ith this metal is accounted for by the circumstances that the ore is found frequently near the surface. and is easily reduced by charcoal and a moderate degree of heat to the state of metal. Tin is fonnd in England, Saxony, Bohemia, Hungary, Chili, Mexico, Billito», Banca, and the Peninsula of Malacca. Malacca furnishes the purest tin, and Cornwall the largest quantity. India imports it chiefly from the Straits Settlements to a varying extent up to 48,372 cwt., valued at Rs. 22,13,323.
Tin occurs in two states of combination, th( peroxide and the rare double sulphuret of tin anc copper ; but it is from the former that the meta] is almost entirely obtained. The peroxide is found —(1) In veins, where it is intimately mixed with several other metals, as arsenic, copper, zinc, and tungsten,—this is common tin-stone ; and (2) in loose rounded masses, grains, or sand in alluvial soil, in which state it is called stream-tin. The former, when reduced to the metallic state, yielch block-tin ; while the latter yields grain-tin, which is the purer of the two, and it is brought into commerce in these two forms. Wood-tin is in reniform and botryoidal masses, or in wedge shaped pieces, which have arisen from their partial destruction ; the surfaces are generally water W0111. Stream-tin is evidently derived from the destruction of tin veins or lodes, the lighter por tions of stony matter having been carried away by the water, which has rounded the fragrnents of the ore. Tin was used by the Egyptians. The Greeks and Romans obtained it through the Phoenicians from England. Tin with the Egyptians formed an ingredient in sorne of their metallic compounds for hardening copper, and they used the alloy for forming swords and spear-heads. Its use has long been familiar to the Hindus for tinning copper, and for various compounds with copper and tin, which are remarkable for their hardness, and for the line sounds which they emit on being struck. Dr. Wight found that an alloy of 10 of copper to 2/ of tin was the best mixture which a native made in his presence. Ancient
British spear-heads are found to consist of 1 of tin to 10 of copper, and an ancient knife, of 1 of tin to 7i of copper. Mr. Aikin found that 8 of copper to 1 of tin formed the hardest alloy.
The Etu.opeau alloys of tin are as under :-1 oz. of tin to 1 lb. copper, a soft gun metal ; oz., harder, fit for wheels to be cut with teeth ; to 2 oz., brass ordnance ; 2 oz., hard bearings for machinery ; 2i oz., very hard bearings for machin ery ; 3 oz., sof t musical bells ; 31y, oz., Chinese gongs and cymbals ; 4 oz., house bells ; oz., large bells ; 5 oz., largest bells ; 71 to 81 oz., speculum metal. The tin alloy is scarcely malleable at 2 ounces ; it soon becomes very hard, brittle, and sonorous. Smiths of India render the mixed metal malleable with greater proportions of tin ; so do the Chinese for' their gongs and cymbals, by gently striking it -while hot at repeated beatings. Some years ago bronze sheathing for ships was prepared on the same principle. Teling people call such malleable bell metal Akkansu. It is formed into vessels for containing acid food, buttermilk, etc.
The island of Banca, which is a continuation of the mainland of Malacca. is of granite, graduating into syenite, and flanked by silurian slates and quartzites. The ore was worked to a considerable extent during the 18th century by the sultans of Palerabang, the yield having reached 4000 tons per annum. This production afterwards fell off very much, and when the Dutch obtained the island in 1821, it did not amount to half that quantity, although it now surpasses it, viz. :— 1820-29, 1500 tons; 1830-39, 2700 tons; 1840-49, 4100 tons ; 1850-59, 5200 tons; 1869-69, 4700 tons; 1870-77, 4400 tons. The average annual amount of tin per mine does not exceed half a ton, though the , washings at Blinjoe average one ton per annum. The island of Billiton, as a tin-mining district, only dates from 1850, the yield for the first ten years being only 180 tons. Since then, however, it has risen so rapidly that between 1870-76 over 3600 tons Nvere .raised per annum. The population of Billiton has increased from 1400 in 1860 to 28,000 in 1876 ; of these a good number consisted of Chinese miners. There were only 400 of these in 1860, and 4300 in 1873.