This valuable metal is plentifully diffused throughout nature, pervading almost every thing, so as to be detected even in plants and animal fluids, and is the chief cause of color in earths and stones. It is found in large masses, and in various states, in the bowels of the earth. In the museum of the Academy of Sciences at Petersburgh is a mass of native iron twelve hundred pounds weight. In the northern parts of the world whole mountains are formed of iron ore, and many of these ores are magnetic. Of the English ores, the common Lancashire hematite produces the best iron. This metal is found in solution in many natural springs, and gives the character to all our chalybeate waters: besides which, there are some springs which contain iron in combination with sulphuric acid. These are called vitriolated waters. There are several in this land; but those at Chadwell near London, and at Swansea in Glamorganshire, are probably the most important. As this metal possesses so many properties, exists in so many different states, and is capable of being applied to such a variety of excellent purposes, it is certainly the most useful of all the products of the mineral kingdom. It was used in the time of Moses, in whose writings Canaan is mentioned as “a land whose stones were iron.” The Greeks understood the method of tempering it. Homer, in the ninth book of his Odyssey, describes the fire-brand driven into the eye of Polyphemus, as hissing like hot iron immersed in water. The advantages which we derive from the magnetic property of iron are incalculable. To this we are indebted for the _mariner’s compass_, by which man is enabled to traverse the ocean, open a friendly or commercial intercourse with every quarter of the globe, and to steer his course with the utmost accuracy. “Tall navies hence their doubtful way explore, And ev’ry product waft from ev’ry shore; Hence meagre want expell’d, and sanguine strife, For the mild charms of cultivated life.” Iron may be moulded by the hammer into any form, and united into as many parts as the workman pleases, without rivets or solder. Were it not for this peculiar quality, many works of great importance could never have been executed. A most stupendous fabric, achieved by means of welded iron is the Chinese bridge of chains, hung over a dreadful precipice in the neighborhood of Kingtung, to connect two high mountains. The chains are twenty-one in number, stretched over the valley, and bound together by other cross chains, so as to form a perfect road from the summit of one immense mountain to that of the other.