Ciiat. II.

COMPOSITION AND USE OP MINERALS.

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being laid on one side; when the dam is let out, the Hood of water, rushing down, tearsup the earth and stones, and lays bare new surfaces, when men and boys go into the ravine,and pick up all the ore left by the water. Hushing is chiefly carried on where theravines disclose new veins, and the water running along tears up the stones containing themetal. Rainy weather, which enables a dam of water quickly to be collected, w favour-able to hushing. The work is as easy as washing the ore, and wages much the same,according to the ages of the boys or persons employed. There are many hushing placeson the road-side from Weardale to Nent Head, in Alston Moor.

Washing the Lead Ore. — The object of washing the ore after it has been brought fromtile mine is to separate the lead from the limestone, sandstone, barytes, or other matterwith which it is united or mixed up. Some men, and very many boys under 13, andyoung persons under 18, are employed; as this operation depends on a supply of water,it is necessarily suspended by the frost, and when it has permanently set in, the work isdiscontinued altogether until the spring; it is also partially liable to be interrupted in dryweather, in places where water is not abundant. It is a great advantage to a mine whenit is situated near a river, or a large and copious burn of never-failing water ; but frequentlyit is necessary to take advantage of the smallest streamlets, and artificial means are usedto collect water by dams, the outlets of which can be stopped up at nights, or when thepeople are not employed. In East Allendale, there is a dam which covers 7 acres of land,but in general they are not so large.

Formerly the washing of the ore was a very simple and rude operation. It was placedon a huddle or sunk space of ground, with a gentle declivity, so that water coming at oneend might slowly flow over the stony bottom to the other, carrying off the loose dirt,clay, or pulverised stone ; the solid pieces of ore were broken by a rude instrumentcalled a hucker, not yet entirely out of use. This instrument consists of a flat pieceof iron, about the size of a man’s hand; at the back is a broad ring, through which isthrust a piece of wood for a handle. 'Hie boy takes this in his hand, and striking theore, breaks it into pieces, by which means the water carries off the earthy matter,and leaves the metal behind. The large pieces of lead, thus separated from extraneousmatter, are carried away in a state fit for the smelting mill: other pieces are put intosieves. In the distant fells, which will not afford the expense of machinery, and where,also, there may be but a small supply of water, this mode is still in use ; a few persons arealso employed as auxiliaries to washing establishments, working at huddles along the sideof a gill, taking advantage of the streams of water which flow down after a heavy fallof rain.

It is obvious that in this mode of washing many small particles of lead must be carriedaway, although this is in part obviated by the water falling into pits, and depositingmuch of the lead. About forty years ago crushing-mills were introduced, and other im-provements have since been made, by which the lead is separated from the earthy matterat much less expense, and a greater proportion of lead is obtained : mines are thus renderedmore profitable, and some, which, on the old system, would not have yielded a profit, cannow be worked to advantage. Preliminary to the operation of the crushing-mill the largerportion of ores are picked out, and sometimes large pieces of pure Galena , without anyearthy matter, which may be broken with the hammer from the stone, are carried at onceto the bingstead, requiring no washing. The ores are at all times placed upon bars of iron,called a grating, and a stream of water flows upon them ; the smaller pieces are carried bythe water through the bars, and down an inclined plane to a place below; those too large toget through remain upon the grating; some of these are dead pieces of stone containing nometal, which are picked ofT by boys and thrown aside ; the remaining matter of ore andstone goes to the crushing mill. Much depends on the nature of the stratum from whichthe ore is obtained; some found in a stratum of barytes comes out in dust or small frag-ments, and may be carried by the waggons, so as at once to be let down, by opening thehole in the bottom of the hopper, which is over the mill; where the pieces are of alarger size, they must previously be broken and grated. The crushing mills require aplentiful supply of water to drive the wheel, as well as to perform the other subordinateoperations; they are of various powers, and have the great water-wheel in the middle : onone side are the wheels which break the house ore, or the ore in its rough state, and on theother side are the chat mills , for breaking and bruising the ore which has been crushed orground into smaller pieces.

The Douse Ore is discharged from the hopper by a machine called a shoe, or a boy or youngperson gradually lets it out. In either case it falls between two rollers, deeply fluted, whichrevolve and work into each other ; a body of water falls down between them at the sametime. In passing between these fluted rollers the ore is crushed into smaller pieces, whichwith the rest fall down two inclined planes, one to the right and the other to the left, witha pair of rollers at the extremity of each : these are smooth, and between them the orepasses along with a body of water, and is further ground, and falls into pits below. Acertain portion of the ore still escapes, as, when a large piece comes between the rollers,

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