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PROPERTIES OF SILVER.

masses. The colour of native silver is white, often tarnished.Silver alloyed with gold forms the auriferous native silver ore.The colour of tins ore is a yellowish white. It has much me-tallic lustre. The antimoniated silver ore belongs to this class.Silver combined with sulphur, forms the sulphurated oxid ofsilver, or vitreous silver ore. This ore occurs in masses, some-times in threads, and sometimes crystallized in cubes or regularoctahedra. Its colour is dark bluish grey, inclining to black.Its fracture is uneven, and its lustre metallic. It is soft enoughto be cut with a knife. It is sometimes found alloyed with an-timony (grey silver ore.) Silver united to muriatic acid formsthe corneous silver ore (muriate of silver,) which appears underdifferent colours and shapes. Silver united to oxigen constitutesthe calciform silver ore, of which there are several varieties. Thecolour of these ores is a lead-grey, or greyish black. They oc-cur massive, disseminated, and crystallized.

Germany, and other countries of Europe, but more especiallyPeru and Mexico in South America, contain the principal silvermines. There are, however, silver mines in Ireland, Norway,France, and many other parts of the world..

-PROPERTIES OF SILVER.

Pure silver is very brilliant, white and sonorous. It is themost splendid of all the metals. Its specific gravity ds from10.4/4 to 11.091 according to the state of its density. It isexceedingly ductile and tenacious. It may be beat out intoleaves only part of an inch thick, and drawn into wire

the thousandth part of an inch thick. It melts at 28° of Wedg-wood's pyrometer. Exposed to a temperature considerablyhigher it becomes volatilized. Atmospheric air has no effectupon it except when it contains sulphureous vapours, sulphurat-ed or phosphorated hidrogen gases. It unites to phosphorus andsulphur. It slightly unites with the brittle acidifiable metals/