V.
436. Further: it has since occurred, that a Machine in the Form of a gun-barrel, extended in all its Dimensions, will probably answer every Intention.
And of this Kind are the hollow cylindrical Tubes, of different Lengths, and about a Foot in Diameter,[138] which are cast, for the Conveyance of Steam, from the Boiler of a Steam-Engine.
Such a one, (previously lined with a Cylinder of Copper, or malleable Iron, to prevent the Adhesion of the Borings, when reduced to a Calx by the Admission of Steam;) might be placed horizontally over a Stove, (with or without a Chimney) and surrounded with red hot Coals.
The Ton of Borings might be deposited at one End of the Tube; and, by Means of the Air-tight flexible leathern Case, be pressed with a Rake, gradually into the Fire, and beyond it when calcined.
Care must be taken to make the Apparatus nearly Air-tight.
The Steam shoud pass into the Tube, from below: and the Gass be conducted towards the Balloon throu’ another Iron Cylinder, nearly equal in Diameter and at right Angles with the first; lying also in an horizontal Direction; along the Ground.
The Tubes might be forged or cast, so as to form but one rectangular Piece.
The further End of the second Tube shoud communicate with a third, made of Tin, and bent downwards about a Foot; thence at right Angles, for six Inches: then to rise up, also at right Angles, the Length of six Inches more.
The Tin Tube is to descend into a Cistern of cold Water, made to flow over continually, by a fresh Supply; and into which, a few Lumps of Quicklime shoud be thrown.
The Gass, which will press upwards throu’ the Water, is to be received into an inverted Funnel, and thence (as in Section 339, Art. 2.) conveyed to the Balloon.