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All the simple substances with which we are at present acquainted, are light, caloric, or heat, oxygen, nitrogen, the metals, some of the earths, and the four simple combustibles, carbon, hydrogen, sulphur, and phosphorus. But to resume our original subject.

" Crude iron is in three states, white, grey, or black, according as it contains a larger proportion of carbon, an exact proportion of carbon and oxygen, or a larger proportion of oxygen.

“ To render the iron malleable, it must be freed from the carbon and oxygen which it contains; by being fused, and kept in that state for some time, stirring and kneading it all the while; by this the carbon and oxygen unite, and are expelled in the form of carbonic acid gas. It is then subjected to the action of large hammers, or to the pressure of rollers by which the remaining oxyd of iron and other impurities are forced out. The iron is now no ger crystalli nular in its texture ; it is fibrous, and ductile, and is in a purer state, though far from being absolutely pure. It is capable of being welded and worked by hammers into any form. It is now called forged or wrought iron.

• There are several varieties of iron in this state, arising from the intermixture of other substances. There is one kind of forged iron, which when cold is ducule, but when heated, is extremely brittle ; it is also fusible. This is termed hot short iron. Cold short-iron possesses precisely the opposite properties, being highly ductile while hot, but when cold, extremely brittle. The causes of these peculiarities have not been perfectly explained.

“ Iron is capable of being reduced to a third state, which is that of steel. It is converted into steel by exposing it to heat in contact with carbonaceous substances, which unite themselves with it. Thus we have three states in which iron may exist, viz. cast-iron, forged-iron, and steel.

Cast-iron contains too.great a quantity of carbonaceous substance: it may be called steel too much steelified ; it is therefore exceedingly brittle, and not at all malleable.

Forged iron is iron purified from all foreign substances. And in regard to its property of being welded, we may juuge from the following account I am about to relate ; for were it not for the property which iron has of being welded, that is, united in various parts without the assistance of rivets or solder, this very plentiful metal would be useless for many

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purposes; but as it is, what may not be accomplished by it! The most stupendous metallic fabric ever executed by man, is the Chinese “bridge of chains," hung over an awful precipice near Ringtung, to connect two mountains. In this bridge there are twenty-one chains, stretched over the valley or abyss; these are bound together by other chains which cross them. The whole forms a perfect and safe road, extending from the summit of one mountain, to that of the other. A bridge, upon a similar principle, and of the same material, is now in the act of being erected over the Menai Strait, (to connect Wales with the Isle of Anglesea), by Mr. Telford, the engineer.

“ Steel is formed by bedding in charcoal, in a close furnace, alternate layers of malleable iron and charcoal, and exposing them to a strong fire for six or eight days. This process is called cementation. During this operation, the iron combines with a quantity of carbon, and is converted into blistered steel. This is either rendered more perfect and malleable, by subjecting it to the operation of the hammer, or it is fused, and cast into small bars, forming caststeel.

“ Steel holds a middle rank between cast and forged, or malleable iron. It is composed of very small grains; and when hot, possesses a considerable degree of malleability. It is specifically heavier than forged iron.

“ It is denser than forged iron, but it is not harder. To communicate to it the necessary hardness, it must be tempered ; that is to say, after being exposed to a greater or less degree of heat, according to the required degree of hardness, it must be suddenly cooled by immersion in cold water. Tempering renders it harder, more elastic, and more brittle, It may be made so hard as to scratch glass. Steel, thus hardened, may have its softness and ductility restored, by again heating, and suffering it to cool slowly.

“ A polished bit of steel, when heated with access of air, acquires very beautiful colours. It first becomes of a pale yellow, then of a deeper yellow, next reddish, then deep blue, and at last bright blue. At this period it becomes red hot, and the colours disappear; at the same time that the metallic scales, or the black imperfect oxyd of iron which is formed, incrusts its surface. All these different shades of colour indicate the different tempers the steel has acquired by the increase of heat. Artists have availed themselves of this property, to give to surgical and other sharp instruments those degrees of temper, which their various uses require.

Tempered steel is more elastic, and harder than iron. Its use is too well known to require elucidation.

" Wootz, a metal brought from the East Indies, was examined by Dr. Pearson, who discovered that it was iron united carbon, and also to oxygen.

“ The sulphate of iron is common copperas in an impure state."

Having said thus much upon iron, I will mention copper and lead. Copper is found native, but in very small quantities; it is generally met with in the state of an oxyd, or united to acids and sulphur. The copper mine of the isle of Anglesea, is perhaps the largest known mine of that metal in the world. Pure copper is of a red colour, very tenacious, ductile, and malleable.

“Nitrate of copper is copper dissolved with nitric acid.

The sulphate of copper, or what is commonly called blue vitriol, is sulphuric acid, concentrated with copper.

“ Verdigrise is acetous acid, imperfectly oxydated with copper.

“ Copper may be alloyed with most of the metals. As an alloy of silver, it renders it more fusible; this mixture is employed as a solder for silver plates. Copper, when alloyed with tin, forms bronze, a metal used for making bells, cannon, statues, &c. When alloyed by cementation with the oxyd of zinc, called calamine, it forms brass. With arsenic, it forms white tombac. The salts found with copper, have a poisonous quality.

“ Copper is employed for making kitchen utensils, but very improperly; for as these vessels are liable to be corroded by the salts and acids used in culinary preparations, they often become dangerous, and may thus make us swallow slow poison. Kitchen utensils of tinned-iron are far preferable, because iron possesses no quality injurious to health.

** Lead is seldom, if ever, found in the native state. It is chiefly mineralized by sulphur, and is then called galena. When exposed to heat with access of air, it fuses, and is oxydated at the surface. If this oxyd be removed, more is formed, and thus the whole may be converted into grey oxyd of lead. This oxyd, when exposed to a strong heat, is con. verted into a yellow oxyd, called massicot. If this yellow

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oxyd be exposed to a still more violent heat, it assumes a beautiful red colour, and becomes red lead, or minium ; litharge is a semi-vitrified oxyd of lead, obtained by keeping a stream of air upon fused lead : it is generally procured in the process of separating silver from lead.

“ If litharge be exposed to a strong heat, it becomes converted into glass of lead, which forms the basis of the common glazing for earthen-ware.

“ The acetous acid corrodes lead, and the result is a white oxyd, known upder the name of white lead.

“ All the oxyds of lead are soluble in vinegar, and form acetite of lead, known under the name of sugar of lead.

“ Lead is applied to a great variety of uses in the arts, which do not require illustration. Lead forms alloys with other metals which are used as solders.

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SECTION VII.

THE MINES OF DALECARLIA.

As they entered the province of Dalecarlia the scenery became wild and picturesque, to a great degree. Fahlun is environed by mountains and lakes, and as our travellers traversed this independent region they experienced many instances of that frank and generous hospitality which is seldom found where the mind is fettered by slavery. The little groups of female peasants they occasionally met with, dressed in their short jackets and many coloured petticoats, gave a life to the dreary scene around them. They are in general well formed, and many of them would present good models for a Hebe. Their countenances are open and frank, their

eyes blue and ea pressive ; and their manners are pleasing and attractive. So hardy are they that it is not unusual with one of these damsels, to wash her linen in a brook and put it on wet and so let it dry. Their food generally consists of black bread and water : but content, that world of wealth, gives to their homely fare the flavour of nectar and ambrosia.

“ Health and industry need no tempting cates,” said Dr.

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