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This instrument promises to be more effectual than ei-ther of the preceding, though in this country it can be oflittle use, so high a fall of water being rarely to be pro-cured, at least in those places where smelting furnacesare established.

IV. A funnel and pise with air holes, inserted into an

air vessel.

At Lead hill's in Scotland.

In N°. 576 of the Philosophical Transactions, in theyear 1745, Mr. Stirling describes a machine erected in Scot-land, for blowing air into the furnaces in which lead oresare smelted ; and for conveying fresh air into the works,so as to save the trouble and expence of the double driftsand shafts, and the cutting of communications betweenthem.

A stream of water runs into a wooden funnel, so as tokeep it always nearly full : the height of the funnel isfive feet, and the diameter of its throat three inchesand a half. The neck of the funnel is inserted into anupright pipe, whose diameter is five inches and an half,and its length fourteen, fifteen, or sixteen feet: imme-diately under the throat of the funnel, four air holes aremade in the pipe, at equal distances round it, about aninch and a half wide, sloping downwards from the outsideto the inside.

The lower end of the pipe enters into a wooden tub,close at top, but without a bottom, fix feet high and fiveand a half wide, funk into a pit dug in the ground, andwell rammed about with clay : in the middle of the tub,directly under the pipe, is a flat stone about two feethigh, for the water to fall upon ; and into the top of thetub is fixed a wooden pipe for carrying off the air, com-

N n municating