This Muffle is to be nearly filled with a Ton of Iron Borings: (the Ends to be made up, to prevent the Borings from falling out into the Tube;) the Muffle itself is to be supported by a Cradle[139] of the same Form, made of strong Copper Wire,[140] like the open Iron-Wire-Fenders: and the whole is to be thrust into the Tube.
The Length of the Muffle depends on the Quantity of Borings that are intended to be used.
The Ends of the Tube shoud not be made so strong as the Tube itself: that, if an Explosion happens, they may give way first, and prevent a Rupture of the Tube: not that any Danger is to be apprehended, that such an Event will take Place, so long as the Steam-Pipe is attended to, by a proper Person: the above Caution being only given, to prevent a Possibility of Rupture.
Each End shoud be cast, or forged with a hollow Handle; and shoud screw into the Tube.
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.