Inventors before Savery’s time were wont to make a great mystery of their inventions; but he proclaimed that there was no mystery whatever about his machine, and he believed that the more clearly it was understood, the better it would be appreciated. He acknowledged that there had been many pretenders to new inventions of the same sort, who had excited hopes which had never been fulfilled; but this invention which he had made was a thing the uses of which were capable of actual demonstration. He urged that the old methods of raising water could not be carried further; and that an entirely new power was needed to enable the miner to prosecute his underground labours. “I fear,” said he, “that whoever by the old causes of motion pretends to improvements within the last century does betray his knowledge and judgment. For more than a hundred years since, men and horses would raise by engines then made as much water as they have ever done since, or I believe ever will, or, according to the law of nature, ever can do. And, though my thoughts have been long employed about water-works, I should never have pretended to any invention of that kind, had I not happily found out this new, but yet a much stronger and cheaper force or cause of motion than any before made use of.” He proceeded to show how easy it was to work his engine,--boys of thirteen or fourteen years being able to attend and work it to perfection after a few days’ teaching,--and how he had at length, after great difficulty, instructed handicraft artificers to construct the engine according to his design, so that, after much experience, said he, “they are become such masters of the thing that they oblige themselves to deliver what engines they make exactly tight and fit for service, and as such I dare warrant them to anybody that has occasion for them.”[31] Savery’s engine, as described by himself, consisted of a series of boilers, condensing vessels, and tubes, the action of which will be readily understood with the help of the annexed drawing.[32] [Illustration: SAVERY’S ENGINE.] [31] ‘The Miner’s Friend, or an Engine to Raise Water by Fire, described, and of the manner of fixing it in Mines, with an account of the several uses it is applicable unto; and an answer to the objections made against it. By Tho. Savery, Gent.’ London, 1702.