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PROPERTIES OF COPPER.

This ore generally exhibits a very fine grass-green, emerald-green, or apple-green colour. It is found in solid masses of anindeterminate shape. It has often a beautiful sattin-like appear-ance, or silky lustre.

It also exists mineralized by the muriatic, acid, sulphuric acid,arsenic acid, &c. Copper mineralized with sulphur is calledvitreous copper ore. Its colour is generally lead-grey. Com-bined with sulphur and iron it forms the azure copper ore and alltlie varieties of copper pyrites. Mineralized with sulphur, arse-nic, iron, and zinc, it constitutes the brown or llendose copperores, 'of which there are many varieties. Copper mines areabundant in Britain, Germany, &c.

PROPERTIES OF COPPER.

Pure copper is of a rose-red colour, very sonorous, very tena-cious, ductile, and malleable; of a considerable compactness;moderately hard and elastic. Its texture is granulated, and sub-ject to blisters. It crystallizes in quadrilateral pyramids. Itsspecific gravity is between 7 . 7 SS and 8.534. When rubbed itemits a disagreeable odour. It melts at 27 0 of Wedgwood’spyrometer. At a higher temperature it burns with a beau-tiful green flame. It is a good conductor of caloric, of electricity,and of galvanism. Exposed to the air it becomes brown and atlast green by absorbing carbonic acid. When heated it turnsblue, yellow, violet and brown. It readily fuses with phospho-rus and unites to sulphur when finely divided by mere trituration.It does not decompose water at the temperature of ignitibn. Itis acted on by the greater number of the acids. Nitric acid actson copper with great vehemence. Sulphuret of potash combineswith it in the dry and in the humid way. It is capable of alloy-ing with the greater number of the metals. With zinc it formsthe compound metals called brass, pinchbeck and others: withtin it forms bell-metal and bronze. It unites to the earths