Magnet, or Loadstone, a kind of ferruginous stone, which in weight and colour resembles iron ore, though it is somewhat harder and more ponderous. It is occasionally discovered In iron mines, being sometimes in large masses of different forms and sizes, that are partly magnetic, and partly metallic. Its colour varies according to the country whence it is obtained; the best magnets, which are imported from China and Bengal, are of a deep blood-colour; those of Arabia are reddish; those of Macedonia, blackish; and such as are found in Germany, Hungary, England, and other parts of Europe, have the appearance of unwrought Iron.

The distinguishing properties of the magnet are, 1. Its attraction of iron, as well as every matter containing ferruginous particles ; and 2. Its inclination to the poles. Hence it is of essential service in navigation, and is employed in constructing the mariners' needles, both horizontal and inclinatory.— As this subject, however, is but distantly connected with our plan, we shall merely state the most simple method of making artificial magnets, which possess the virtues of the genuine loadstone, and have been found very useful in extracting particles of iron from the eye, and other delicate parts of the human frame.—Cavallo directs the scales, which fall from red-hot iron, when hammered, to be reduced into a fine powder, and mixed with drying linseed-oil, so as to make a stiff paste; when it may be moulded into any form required. This mixture is to be put in a warm place for some weeks, till it become perfectly dry, and hard; after which it may be rendered powerfully magnetic by the mechanical application of the magnet. But this friction of the two metals should be performed in a direct horizontal line from north to south ; by which simple process, if continued for a sufficient length of time, even two flat pieces of iron or steel may be easily imbued with the magnetic fluid, so as to evince, in a considerable degree, the properties of the genuine loadstone, without having been touched by the latter.

In order to increase the attractive power of the native magnet it is frequently armed, that is, cased, capt, and provided with thin iron plates or bars, after its poles have been polished and pro-perly regulated. Thus, it will-sup-port a weight 20, 40, nay 100times greater than it could bear in its natural state ; and, by loading it with ponderous bodies, its force, instead of being diminished, is considerably improved. On the contrary, by charging a loadstone with an inadequate weight; exposing it to heat, rust and lightning; by keeping it in an improper direction to the poles, or frequently dropping it on the floor, its virtues will soon be diminished.