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some of the most important uses of life, where strength, rather than beauty, is necessary; such as anchors, plough-shares, horse-shoes, chains, bars, and nails. Cast-iron is useful for pots and cauldrons, grates and stoves. Cannon and cannon-balls are also made of it. CHARLES. The uses of iron and steel cannot be enumerated: most tools, both in husbandry and other arts, are made of one or the other. But it has the great defect of being very subject to rust.
AUGUSTA. When I was out of health, I was ordered to drink water from a chalybeate spring, which my governess said was impregnated with iron.
MRS. HARCOURT. Water which dissolves particles of iron as it runs beneath the surface of the earth, is recommended as beneficial in several disorders. Iron is given as a medicine, in many forms; and is thought to possess considerable power, as a bracer of relaxed habits. Waters which are chalybeate, may be known to be so by being turned black like ink, upon the addition of a little powder of nutgalls. This test enables the chemist
to judge of the presence of iron in any kind of solution.
SOPHIA. Is not the loadstone a kind of iron?
MR. HARCOURT. It is a species of iron ore, which is both hard and heavy: it possesses extraordinary powers, attracting iron to itself, and communicating this property to any piece of iron that is rubbed with it; but what renders it of most important advantage in civil life, is a peculiar tendency which it has of pointing to the poles of the earth. The ingenuity of man has applied this unaccountable quality to the construction of the compass, by which ships are guided in their course over the trackless ocean. Iron is the produce of all mountainous countries: the northern parts of Europe supply us with great quantities of this most useful metal. The tops of ferruginous mountains are frequently crowned with resinous trees, such as the pine, the fir, and the cedar, the charcoal of which is particularly adapted to melting the iron. These trees are often covered with mosses, some species of which catch fire from
the smallest spark. Thus, nature has placed those materials on the same spot, which require the assistance of each other to render them subservient to the uses of man.
CECILIA. Although other countries excel Great Britain in rich mines of gold and silver, she is celebrated for her tin-mines. Cornwall and Devonshire abound in this metal: and I have read that the Phoenicians, a people of Asia, traded to this country for that article, several hundred years before the Christian era.
MR. HARCOURT. The application of the information we gain from books, on proper occasions, is the best end of reading; for merely turning over a great number of volumes, without increasing our knowledge, is a waste of time. Tin is of a whitish colour, softer and less elastic than any other metal. The ore of tin is the heaviest of all metallic ores, though tin is the lightest of metals, which arises from a combination of other substances. When bent it makes a crackling noise, fuses easily, and calcines if long exposed to the fire. It possesses the capacity of malleability, but not that of ductility.
MRS. HARCOURT. In the Cornish mines, large pieces of timber entire, are sometimes found by the miners at the depth of forty or fifty fathoms: they must have grown originally there, many ages ago; since which time the earth above them has been deposited, and not only deposited, but in some instances displaced by some violent convulsion of nature. AUGUSTA. Are the uses of tin very considerable?
MR. HARCOURT. In the form in which we generally see it, it is combined with other metals. Its cleanliness, and freedom from rust, are the causes of its being used as a lining for copper vessels, by which means they are rendered safe for the purposes of cooking, &c. The tinned wares in common use, are plates of iron covered with tin. The plates are first steeped in an acid water, till they are a little corroded; they are then scoured with sand, by which they are made very smooth and fine. Thus prepared, they are dipped into boiling tin: when cooled, they are ready to be formed into various utensils. If they are washed with a mixture of acid and water, the
beautiful arrangement of the particles of tin appears in stars, and waves, and clouds, of almost infinite variety; and fine colours may afterwards be imparted to this ware by varnishes.
HENRY. How are they joined together, when they are required to make any thing round, as a mug or tea-kettle?
MR. HARCOURT. They are soldered with a mixture of tin and lead. A solution of tin in aqua regia, added to the tinctures of cochineal, gum-lac, and some other red tinctures, heightens their colour, and changes it from crimson or purple, to a fine scarlet. The superiority of our fine scarlet cloths is attributed to the addition of this ingredient in the dye. MRS. HARCOURT. Tin is used in the making of looking-glasses, or at least in giving them their power of reflection. A sheet of tinfoil, made similar to leaf-gold, is laid down, perfectly smooth, upon a stone slab, and as much quicksilver poured over it as is sufficient for the glass to swim on, it being previously well cleaned with powdered chalk or whiting; the glass is then covered all over with small leaden weights, to press it down,