TIME - KEEPERS ; TIME - PIECES. [CrmowonthrEns ; Chkeits and WATCHES.] TIN. This metal is one of those which were earliest known, though it occurs in com paratively few countries. It is found in England, Saxony, Bohemia, Hungary, the isle of Banca, the peninsula of Malacca, in Chili, and Mexico. Malacca furnishes the purest tin, and Cornwall the largest quantity. It occurs in two states of combination, the Peroxide of Tin. and the Double SolpAprret of Tin and Copper : this last is rather a rare substance, and it is from the former that the metal is almost entirely obtained.
The peroxide is found in Cornwall in com bination with other metals, in Tin.Stone ; and in loose rounded masses called Stream Tin. The former, when reduced to the metallic state, yields Block-Tin while the latter yields Grairt-Tin, which is the purer of the two. The tin-stone, which contains 77 per cent. of pure tin, occurs in q crystalline form, as well as in masses; but strearntin is uncrystallised, and bee evidently been derived from the destruction of tin veins or lodes, the lighter portions of stony matter having been carried away by tlie,water, which has rounded the fragments pf the ore.
This metal is of a colour, very soft, and so malleable that it may be reduced into leaves 1.1000th of an Mch thick, called tin-foil it suffers but little change by expo sure to the air. Its tenacity is but slight, so that a wire of 1-15th of an inch in diameter is capable of supporting only about 31 lhs. : a bar a quarter of an inch in diameter was broken by 296 lbs. weight, Tin is inelastic, but very flexible, and when bent it produces a peculiar crackling noise. When rubbed it imparts to the fingers a Peenliar smell, which remains for a considerable time. Its specific
gravity is about 7.29: at 41r Ftdar. it fuses, and if exposed at the same time to the air, its surface is tarnished by oxidation, and eventually a gray powder is formed, When heated to whiteness it takes fire, and burns with a white flame, and is converted into peroxide of tin. If slowly pooled after fusion, it exhibits a crystalline appearance on solidi fying.
The combinations which tin forms with oxygen, chlorine, sulphur, and iodine, and those which the oxide of tin forms with the various acids, are valuable in calico printing and many other of the practical arts.
Most of the malleable metals are rendered brittle by alloying with tin. It combines readily with potassium and sodium, forming brilliant white alloys, which are less fusible than tin. With Arsenio it forms a metallic mass which is whiter, harder, and more aono rous, than pure tin. With antimony tin forms a white, bard, and sonorous alloy. Bismuth forms with tin an alloy which is more ftsible than either of the metals separately, a mix ture of equal weights Inching at 212. ; this compound is bard and brittle. Copper and tin form alloys which are well known and highly nseful—Be/1 Metal and Bronze, With mercury tin readily amalgamates, and the compound is used for silvering mirrors. Tin forms with iron white compounds, which are more or less risible according to the propor tion of iron they contain, Tinplate is of all the alloys of tin the most useful, and the preparation of this and of pewter are the most extensive applications of this very valu able metal.