3. Nothing can be more fit for serving cities and towns with water, except a crank-work by the force of a river. In the composing such sort of engines, I think no person hath excelled the ingenious Mr. George Sorocold; but where they are forced to use horses, or any other strength, I believe no ingenious person will deny this engine to have the preference in all respects, being of more universal use than any yet discovered or invented. 4. As for draining fens, marshes, &c. I suppose I need say no more than this, that that force which will raise great quantities of water a height of above eighty feet, must necessarily deliver a much greater quantity at a lesser height; and that it is much cheaper, and every way easier, especially where coals are water-borne, to continue the discharge of any quantities of water by our engine, than it can be done by any horse-engines whatsoever. 5. I believe it may be made very useful to ships, but I dare not meddle with that matter, and leave it to the judgment of those who are the best judges of maritime affairs. 6. For draining of mines and coal-pits the use of the engine will sufficiently recommend itself in raising water so easy and cheap; and I do not doubt, but that, in a few years, it will be a means of making our mining trade, which is no small part of the wealth of this kingdom, double, if not treble to what it now is. And if such vast quantities of lead, tin, and coals, are now yearly exported, under the difficulties of such an immense charge and pains as the miners, &c. are now at to discharge their water, how much more may be hereafter exported, when the charge will be very much lessened by the use of this engine every way fitted for the use of mines? For the far greater part of our richest mines and coal-pits are liable to two grand inconveniences, and thereby rendered useless, viz. the irruption and excess of subterraneous waters, as not being worth the expense of draining them by the great charge of horses, or hand labour. Or, secondly, fatal damps, by which many are struck blind, lame, or dead, in these subterraneous cavities, if the mine is wanting of a due circulation of air. Now, both these inconveniencies are naturally remedied by the work of this engine, of raising water by the impellant force of fire. For the water, be the mine ever so deep, each engine working it sixty, seventy, or eighty feet high, by applying or setting the engines one over another, as shall be showed at large hereafter in the following pages, you may, by a sufficient number of engines, keep the bottom of any mine dry; and when once you know how large your feeder or spring is, it is very easy to know what sized engine, or what number of engines will do your business.