Tut. It gains a fine gold-like colour, and becomes harder, more easy to melt, and less liable to rust. Hence it is preferred for a variety of utensils, ornamental and useful. Brass does not bear hammering well, but is generally cast into the shape wanted, and then turned in a lathe and polished. Well—these are the principal things I have to say about copper.
Har. But where does it come from?
Tut. Copper is found in many countries. The Isle of Great Britain yields abundance, especially in Wales and Cornwall. In Anglesey is a whole hill called Paris Mountain, consisting of copper-ore, from which immense quantities are dug every year. Now for iron.
Har. Ay! that is the most useful of all the metals.
Tut. I think it is; and it is likewise the most common, for there are few countries in the world possessing hills and rocks, where it is not met with, more or less. Iron is the hardest of metals, the most elastic or springy, very tenacious or difficult to break, the most difficultly fusible, and one of the lightest, being only seven or eight times as heavy as water.
Geo. You say it is difficult to break; but I snapped the blade of a penknife the other day by only bending it a little; and my mother is continually breaking her needles.
Tut. Properly objected; but the qualities of iron differ extremely according to the method of preparing it. There are forged iron, cast iron, and steel, which are very different from each other. Iron, when first melted from its ore, has little malleability, and the vessels and other implements that are made of it in that state, by casting into moulds, are easily broken. It acquires toughness and malleability by forging, which is done by beating it when red-hot with heavy hammers, till it becomes ductile and flexible. Steel, again, is made by heating small bars of iron with charcoal, bone, and horn shavings, or other inflammable matters, by which it acquires a finer grain and more compact texture, and becomes harder, and more elastic. Steel may be rendered either very flexible or brittle, by different manners of tempering, which is performed by heating and then quenching it in water.
Geo. All cutting instruments are made of steel, are they not?
Tut. Yes; and the very fine-edged ones are generally tempered brittle, as razors, penknives, and surgeons’ instruments; but sword-blades are made flexible, and the best of them will bend double without breaking or becoming crooked. The steel of which springs are made has the highest possible degree of elasticity given it. A watch-spring is one of the most perfect examples of this kind. Steel for ornaments is made extremely hard and close-grained, so as to bear an exquisite polish. Common hammered iron is chiefly used for works of strength, as horseshoes, bars, bolts, and the like. It will bend but not straighten itself again, as you may see in the kitchen poker. Cast iron is used for pots and caldrons, cannons, cannon-balls, grates, pillars, and many other purposes in which hardness without flexibility is wanted.
Geo. What a vast variety of uses this metal is put to!