The ?lethod of casting thin sheets of Lead. Instead of sand, they cover the mould with a piece of woollen stuff nailed down at the two ends to keep it tigb.4 and over this lay a very fine linen cloth. In this process great regard is had to the just degree of heat, so as that the lead may run well, and yet not burn the linen.— This they judge of by a piece of paper, for it takes fire in the liquid lead if it is too hot, and if it be not shrunk and scorched a little, it is not hot enough.
The Alethod of casting Pipes without soldering. To make these pipes they have a kind of little mill, with arms or levers to turn it withal. The moulds are of brass, and consist of twopieces, which open and shut by means of hooks and hinges, their inward calibre, or diameter, being according to the size of the pipe to be made, and their length is usually two feet and a half. In the middle is placed a core, or round piece of brass or iron, somewhat longer than the mould, and of the thickness of the inward diameter of the pipe. This core is passed through two copper-rundles, one at each end of the mould, which they serve to close ; and to these is joined a little copper tube, about two inches long, and of the thickness the leaden pipe is intended to be of By means of these tubes the core is retained in the middle of the cavity of the mould. The core being in the mould,
with the rundles at its two ends, and the lead melted in the furnace, they take it up in a ladle, and pour it into the mould by a little aperture at one end, made in the form of a funnel. When the mould is full, they pass a hook into the end of the core, and, turning the mill, draw it out ; and then, opening the mould, take out the pipe. If they desire to have the pipe lengthened, they put one cud of it in the lower end of the mould, and pass the end of the core into it ; then shut the mould again, and apply its rundle and tube as before, the pipe just cast serving for rundle, &c. at the other end. Things being thus replaced, they pour in fresh metal, and repeat the operation till they have got a pipe of the length required. For making pipes of sheet-lead, the plum bers have wooden cylinders, of the length and thickness required, and on these they form their pipes, by wrapping the sheet around them, and soldering up the edges all along them.