464 Newcomern and Gawley. [Book IV.

outer cells was cooled as they passed through the water in which thelower part of the wheel dipped.

This device of Amontons is rather an air than a steam machine. Ithardly belongs to this part of our subject; but as it may be consideredthe type of most of the steam wheels subsequently brought forward, wehave been induced to notice it here. As a theoretical device, it is highlymeritorious, but as a practical one, of little value. There is in Martyn andChambers’s abridged. History of the Academy of Sciences at Paris, Lond.1742, a full account of this wheel, and of .the experiments from which itwas deduced. (See vol. i, 69.) It was simplified by Leopold.

Towards the close of the 17th Century there lived in Dartmouth , a smallseaport town on the English channel, two mechanics who combined theirenergies to devise a machine for raising water by means of steam. Theirnames were Thomas Newcomen and John Cawley ; the first a blacksmith,but sometimes called an ironmonger, the latter a plumber and glazier.The circumstances that led them to the subject have not been recorded,nor have the particular contributions of each been specified. Their effortswere however eminently successful, for to them belongs the honor ofhaving permanently established the employment of steam as a mechanicalagent. The date of the commencement of their efforts is unknown, butfrom the observation of a Contemporary writer it seems to have been asearly as the first attempts of Savery.

The principal objection of miners to Savery’s machine, viz. the enor-mous force of the steam required, and the consequent frequent explosionof the boilers, &c. was completely avoided by Newcomen and Cawley;for they used steam of little or no greater force than cooks do in commoncauldrons—hence it could never explode a boiler or endanger human life.Savery’s engine had other disadvantages. It was required to be placedmithin a mine or pit, and in no case farther from the bottom than 25 or 30feet; whereas Newcomen and Cawley’s was erected on the surfaoe, nearthe mouth of the shaft. Moreover, in those mines which were previ-ously drained by pumps, it could be used to work these as before, withoutany additional cost for new pipes and pumps; the engine in such cases merelysuperseding the horses and their attendants. Instead of applying steamlike Savery directly to the water to be raised, these mechanics made useof it to give motion to a piston and vibrating beam, and through these tocommon pump rods; hence the device may be considered rather for im-parting motion to machines proper for raising water, than as one of thelatter.

It is in evidence that Newcomen had some correspondence respectinghis machine with Dr. Hooke, and that he was acquainted with what Papinhad previously done. This however might very well consist with theidea of giving motion to a piston originating with himself or partner ; yetas their labors were subsequent to those of the French philosopher, theirClaims to it, if they ever made any, could not be sustained. Their machinein its essential features is a copy of Guerricke’s, and the mode of producinga vacuum under the piston similar to Papin’s; but as Papin did not suc-ceed, the reintroduction of a device similar to his, and its successful appli-cation to the important purpose of draining mines, belong wholly to them;and the merit of doing this was certainly much greater than can e ver beclaimed for the abortion of Papin. Fulton did not invent steam boats,but he was the first to demonstrate their utility and to introduce them intouse here after they had been tried and abandoned in Europe.

It should not be supposed that the piston engine would not have beenrealized at the close of the 17th or beginning of the 18th Century, if Papin-