460 Joints melted by Steam—Origin of Savery’s Engine , [Book IV .

perform what is required, that even those of the most ordinary and meanestcapacity may work it for some years without injury, if not hired or em-ploy’d by some base person on purpose to destroy it;”—that is, by inat-tention or design to permit steam to accumulate within the boilers tili theywere burst. Some device to prevent this was wanting, viz. a safety-valveor something analogous to it; and it is astonishing that he never thoughtof such a thing, but permitted his machine for lack of it to fall into dis-repute.

The miners could not be induced to adopt it, in consequence of thedanger of explosion. “ Savery [says Desaguliers ] made a great manyexperiments to bring this machine to perfection, and did erect several,which raised water very well for gentlemen’s seats, but could not succeedfor mines, or supplying towns where the water was to be raised very highand in great quantities; for then the steam required being boiled up to

such a strength, as to be ready to tear all the vessels to pieces. -.

I have known Captain Savery at York’s Buildings make steam 8 or 10times stronger than common air; and then its heat was so great, that itwould melt common solder, and its strength so great as to blow openseveral of the joints of his machine; so that he was forced to be at thepains and charge to have all his joints soldered with spelter or hard solder.”Ex. Philos. ii, 467.

There has been much discussion respecting the origin of this famousengine ; some writers contending that it was wholly Savery’s own, othersthat he derived it from one of Worcester ’s, or from the Century of In-ventions. Desaguliers asserts that Savery, to conceal its origin, “ boughtup all the Marquis of Worcester ’s books that he could purchase in Pater-noster Row, and elsewhere, and burn’d ’em in the presence of the gentle-man his friend, who told me this.” But as Savery denied being indebtedto any one for it, and as he was certainly a man of great mechanical genius,it is probable that the doctor was imposed upon by his informant. It isnot likely that Savery would have comm itted such an act in the presenceof a witness, when there was not only no necessity for one, but everypossible inducement for secrecy. Many years before the publication ofthis charge by Desaguliers (in 1744) the opinion was prevalent that themachine was not original with Savery. In 1729 Switzer remarks, “otherssay that the learned Marquis of Worcester , in his Century of Inventions,which book I have not seen, gave the first hint for this raising of water.”(Hydr. 325.) Dr. Hutton, in his Math. Dictionary, asserts, though on whatauthority we know not, that Savery knew more of Moreland’s experimentsthan he was willing to acknowledge; and Desaguliers maintains that heinvented the Story of the experiment with the wine flask “ to make peoplebelieve that he had not got the idea from Worcester ’s Century ofInventions.”

In reply to the above it may be remarked, that independently of thosecoincidences of thought that always have and will happen to inventors,there are circumstances which strongly corroborate Savery’s own accountIn the first place, the experiment with the wine flask was one very likelyto occur in the manner he has mentioned, and to a mind like his wouldnaturally lead to a practical application of it. His thoughts, we are told,“ were always employed in hydrostatics or hydraulics, or in the improve-ment of water-works.” Then there is no evidence that he was much ofa reader : had he been conversant with books, he would not have proposedthe propulsion of vessels with paddle-wheels as new. These occurred tohim as they have done to thousands in every age when devising means toincrease the speed of boats; and so it may have been with his steam ma-