Nickel is attracted by the magnet similar to iron but in an inferior degree. Till lately nickel was but little used, but it now forms the basis of those compound metals known as nickel-silver, German-silver, and British-plate, all which varieties are generally employed as an economical substitute for silver; it is also used largely as a foundation on which to deposit pure silver by the electro-plating process, for which purpose it is most admirably suited being very superior to copper in consequence of its color, as the silver always wears off unequally and exposes the ground work of metal beneath. German-silver is composed of copper, nickel, and zinc, in various proportions. Nickel always forms one of the constituents of meteoric iron, those mysterious masses called aerolites, which sometimes fall to the earth.
COAL.
MINERALS.
This, the richest product of the mine, the well-known fuel used in almost every branch of industry as well as for warming our houses, is got from the depths of the earth, where it exists in certain localities forming what are called “coal fields” or “basins.” It is the result of changes produced during many ages upon vegetable matter buried during the various convulsions which the earth has undergone, and pressed into layers or strata of various thicknesses. To raise this valuable fuel, powerful machinery is used and deep shafts are sunk at an enormous expense.
Coal exists in various forms: the following are the most easily recognised:—
1.—Cubical coal; shining and easily broken into squarish fragments. It burns brightly.
2.—Slate coal; dull in color, splits like slate. Burns well.
3.—Cannel coal; dull color, breaks like resin, and somewhat resembles jet. Burns brilliantly, and splits with a crackling noise when in the fire. It affords the best gas.