1. To lay a Plate of Iron, Brass, or Copper, over the Hearth; which, if made of _cast_ Iron, will be apt to crack, in Contact with the Steam; and will also unite with and concrete the Iron Turnings or Gun-Borings into a solid Mass, that woud be separated with Difficulty. 2. To make the Dross-Pit in the Form of a hollow Wedge, narrow at the Top: screwing and luting it to the South Side of the Hearth. It shoud hold the Dross arising from a Ton of Borings; which will be sufficient for the Inflation of a Balloon, to carry one Person. 3. On the North Side is to be erected a Platform of Brick, a Yard square, _floored_ with a Plate of Iron: the inside Surface to be even with the Bottom of the Hearth. 4. The Ton of Borings is to be placed on the _Floor_, and covered with another Muffle, secured and luted to the Side of the Hearth: having a Communication of two Inches high, and one Yard wide, with the Bottom of the Hearth: as the Dross-Pit has. 5. A Brass or Copper Rake is to remain within the two Muffles: to press forward the Borings, spread them over the Hearth; stir them frequently;—by turning the Instrument, scrape them into the Dross-Pit; and apply fresh from the _Deposit_. 6. To perform these manual Operations within the Machine kept Air-tight; it will be necessary, at the exterior End of the Muffle, to fasten a strong leathern Case, made very wide and pliant, and two Yards long: into which the End of the Rake-Handle is to be inserted. III. 434. _The Mode of Operation._ The Borings being spread on the Hearth, and _red_ hot; the Steam Pipe is to be opened, and _instantly_ shut. The Gass being _suddenly_ extricated; the Pipe is to be opened, and shut again as before: the Borings pushed into the Dross-Pit, and a fresh Supply spread. This Process to be renewed, till the Inflation is completed. If it be thought necessary to prevent the Steam from communicating with the whole Depôt of Borings, and so evolve too much Gass; a little Brass Door with Hinges of the same, might be made to hang from the Top of the Communication between the two Muffles: which Door opening inwards, and hanging vertically, woud by the Pressure of the Gass, stop up the Open: and yet, if made strong, _not_ prevent the Operations of the Rake, at proper Times. IIII. 435. The Machine woud be less complex, with one large Muffle, somewhat longer North and South than the Hearth; furnished with leathern Case and Rake. Put in the Borings at one End: keep the Steam-Pipe always open; with a _Hand_ at the Rake; pushing away the Dross, and pressing forwards fresh Borings. 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.