At one time all small lead pipes up to 2 in. diameter were cast in an appliance known as a " staffing and burning machine." This consisted of an iron core, or mandril, of the same size as the bore of the intended pipe, with one end attached to a flange or base, and an outside iron mould, constructed in two halves, and held together by clamps placed round the core, with an annular space between equal to the thickness of the pipe. The mould and core being stood on end, molten lead was poured into it; the mould was then removed, the piece of pipe drawn upwards nearly off the core, the mould then replaced, and more molten lead poured in, the pouring being continued until the bottom end of the previously made pipe was fused, and thus joined to the last one. An appliance of the kind has been in use since 1639, probably before.