Page:Dictionary of National Biography volume 60.djvu/59

 ral information, if asked what they knew about ‘Watt,’ would probably say that he was the inventor of the steam engine. Those who at all study the subject, or are acquainted with mechanical matters, will at once agree that, great as were Watt's merits, they were the merits of an improver upon an existing machine—the fire engine—and were not those which attach to the original suggester of a novel principle of work. Solomon de Caus in 1616, the Marquis of Worcester in 1659 [see, second ], Sir Samuel Morland [q. v.] in 1661, and Denis Papin [q. v.] in 1690, had each of them proposed to raise water from one level to another, in various ways, by the use of steam. It is disputed as to whether any one of these four inventors ever put his ideas into practice. Following these inventors, however, came Thomas Savery [q. v.], who put his ideas of raising water by steam power into real use, and to a very considerable extent.

All the before-mentioned inventors employed the steam, not to drive an engine (as we understand that expression) to work a pump, but they applied it directly to the vessels into which the water to be raised came, either to cause a partially vacuous condition in such vessels, so as to allow the atmospheric pressure to drive the water up into them, or to press upon the surface of the water in the vessels, so as to expel the water up a rising main, to a height dependent upon the pressure above the atmosphere of the steam employed, or, as in Savery's invention, to raise water by a combination of these methods. In Papin's case, pistons were interposed between the surface of the water and the steam. But about 1710 Thomas Newcomen [q. v.], in conjunction with John Calley, invented a ‘fire engine’ which was in truth a steam engine, in the sense in which we now understand the expression; that is, by the agency of steam he caused certain portions of machinery to move, and he applied their motion to work other machines, i.e. pumps. There was not any patent taken out for this engine, but Newcomen and Calley associated themselves with Savery, presumably on account of the existence of Savery's patent, which in those days probably would be held to cover the doing of an act by a particular agent (steam) almost irrespective of the mode by which that agent was employed. Newcomen's engine comprised a vertical cylinder with a piston working within it, which, when it descended by the pressure of the atmosphere acting on the piston, pulled down the cylinder end of the great beam, the other end at the same time rising and raising the pump rods. There was, of course, the boiler to produce the steam, and the condensation of the steam to produce the partially vacuous condition below the piston. An interesting adaptation of the power of a Newcomen engine to produce rotary motion is to be found in the specification of Jonathan Hull's patent of 21 Dec. 1736, or, better still, in the pamphlet that he issued in 1737, where he proposes to apply the steam engine to paddle-wheel propulsion.

Before passing away from the Newcomen engine, it may be well to notice the admirable account given by Belidor, in his ‘Architecture Hydraulique’ (1739–53), of an engine of this construction which had been made in England and was erected in France at the colliery of Fresnes, near Condé. The description is accompanied with complete scale drawings, from which, at the present day, a reproduction of this engine could be made without the slightest difficulty. It will be found that the boiler is provided with the safety valve invented by Papin, and with an open-ended standpipe for the admission of the feed water; this latter arrangement should, at all events, have insured that the pressure never could have attained more than the intended amount, probably two pounds above the atmosphere; but the amusing precaution is taken of covering the top of the boiler with heavy masonry, not for the purpose of confining the heat, but for that of holding down the boiler top against the pressure within. The writer told the late Sir William Siemens this, and was informed by him that, until quite lately, a regulation existed in France making such loading of the boiler top obligatory—a provision, it need hardly be said, not only useless with boilers of the present day, working at several atmospheres pressure, but absolutely harmful, as providing a stock of missiles ready to be fired all over the place should the boiler burst. Except in the matter of better workmanship and of increase in dimensions, the ‘Newcomen’ engine, as applied to the very important purposes of pumping, had remained practically without improvement for the nearly fifty years intervening between 1720 and 1769, the date of Watt's first patent.

Allusion has already been made to the well-known incident of the entrusting to James Watt for repair the model of the Newcomen engine belonging to the university of Glasgow. It turned out that the model was not out of repair, in the ordinary sense of the word, for it had lately been put in order by a celebrated philosophical instrument maker in London; but it was found