The Length of the Tube shoud be such, that the Person who attends the Steam-Pipe, shoud feel no Inconvenience from the Heat of the Fire. Nine Feet woud therefore be a proper Length: the conducting Tube the same. Within six Inches from each End of the Tube which holds the Borings, a Hole, half an Inch in Diameter shoud be drilled across the Middle of the Tube, in an horizontal Direction. Into these, an Iron Axis is to be fitted, (so as to take out _occasionally_) and pass throu’ the Tube: each End of the Axis is to project outwards a Couple of Inches, and to be made _square_, for the Socket of a strong Iron Winch or Handle. Each Axis to be furnished with a strong Chain, of equal Length with the Tube; one End of which Chain is to be riveted, or otherwise fixed, to the Middle of the Axis; and the other, to be fastened _occasionally_ to one Extremity of the Cradle and Muffle: the second Axis and Chain in like Manner, to the other Extremity. The Muffle is to be placed in the Cradle: both are then to be thrust into the Tube, and fastened to the Chain at the farther Axis: in which Position the Muffle may be filled with Borings, and gradually drawn into the Tube; till the same End has reached the Center of the Fire. The nearer End is then to be hooked by the nearer Chain, already wrapped round the nearer Axis: and the light Iron Caps to be screwed on each End of the Tube. 438. The Boiler for Steam may be fixed on any Part of the Tube near the Fire, and near the opposite Axis; so that one Person may attend both the Steam-Pipe, and Axis. The Steam to be conveyed throu’ a small Orifice made in the Bottom of the Tube, between the same Axis and the Fire. 439. As soon as the Materials, above the Center of the Fire, are supposed to be _red_ hot, the Steam-Pipe is to be opened for a Moment and +shut again+. The extricated Gass will be instantly +heard+, rushing throu’ the Vessel of _cold_ Water; and as instantly +seen+ to swell the varnished Linen-Trunk as it passes into the Balloon. The Steam-Pipe is to be regulated by these infallible Signals: and the Process continued, till that Quantity of Borings, that was in the Center of the Fire, and consequently _red_ hot, is supposed to be calcined. At which Time, the Handles are to be applied to the Axis, and the Cradle and Muffle drawn 5 or 6 Inches forward into the Fire. When drawn too far; Recourse must be had to the second Axis. 440. If great Expedition is required, two or three Conductors from the same Tube may be used: and, at the Distance of six or seven Feet from the Fire, _Tin-Conductors_ may be added; taking Care that they are _made_, _applied_, and _continued Air-tight_. THE END. An _alphabetical_ +index of the contents+: Referring to the +sections+ and +notes+, but _not_ to the _Pages_. A. Section. Absorption of Water by Air, _Experiment to prove_ the, 247 Accumulation of Air, _mediocèanal_, 259, 260