As for fixing the engine in ships, when they may be thought probably useful, I question not but we may find conveniency enough for fixing them.
In mines and coal-pits the manner of fixing the engines is this; your pit being sunk, and a sump, or proper well, or bottom cistern, made to receive the water coming from the several feeders or springs. Supposing an engine, carrying three and a quarter inch bore, is to be fixed to deliver water about seventy feet high, constant running a full bore; in such case you make a small room in your shaft or pit, which, together with your shaft or pit, is nine feet square every way. As for example, suppose your shaft six feet by four, take three feet out of one side, and five out of another perpendicular nine feet, making a small floor or platform of boards over that part of the shaft which goes down to your sump or bottom cistern, so you have a complete room big enough for your engine, where ten or twelve people may stand on occasion. This floor may be about eighteen, nineteen, or twenty feet from the water, at the lowest you ever will draw the water into the sump or bottom cistern. If your ground be loose, it is convenient to line this room with brick; if rock, it may support itself. But in this the miner’s judgment must direct him. That the engine will stand best in the side of the pit where most is dug away, you may see in the second figure of the engine, being fixed in a mine. Your pipes, &c. must be fixed with cramps of iron, wood, or such materials as are convenient, to the side of the pit or shaft, so as to make it stand as firm as the very shaft itself. Your furnace must be so contrived, that your flame take a turn or two round each of the boilers, which any brick-layer used to furnaces can do; it being performed by running a row of bricks round them both like a screw or worm, which being contiguous to the wall of the furnaces and the boilers, makes it, as it were, a worm-funnel round them both; from whence you may continue your chimney to the top of your work, which you fasten to the sides of your shafts in the corners as you please, either with iron or wood, or both, according to the nature of the ground. And wherever you make a sudden bend or nook near a right angle in the chimney, have a loose brick or stone to take out the soot, if any should settle in such place, which in long working it may do.
