HARVARD PRINTEDY RICHARD AND JOHN E. TAYLOR, RED LION COURT, FLEET STREET. THE STEAM-ENGINE, AND THE DISCOVERIES OF JAMES WATT. ALTHOUGH the plan of this new edition of Beckmann's History of Inventions and Discoveries' was to confine it to the subjects treated of in the original work, yet we feel it imperative to make an exception in favour of the Steam-Engine, the most important of all modern inventions. The power of steam was not entirely unknown to the ancients, but before the æra rendered memorable by the discoveries of JAMES WATT, the steam-engine, which has since become the object of such universal interest, was a machine of extremely limited power, inferior in importance and usefulness to most other mechanical agents used as prime movers. Hero of Alexandria, who lived about 120 years before the birth of Christ, has left us the description of a machine, in which a continued rotatory motion was imparted to an axis by a blast of steam issuing from lateral orifices in arms placed at right angles to it. About the beginning of the seventeenth century, a French engineer, De Caus, invented a machine by which a column of water might be raised by the pressure of steam confined in the vessel, above the water to be elevated; and in 1629, Branca, an Italian philosopher, contrived a plan of working several mills by a blast of steam against the vanes; from the descriptions, however, which have been left us of these contrivances, it does not appear that their projectors were acquainted with those physical properties of elasticity and condensation on which the power of steam as a mechanical agent depends. In 1663, the celebrated Marquis of Worcester described in his Century of Inventions, an apparatus for raising water by the expansive force of steam only. From this work we extract the following short account of the first steam-engine. "68. An admirable and most forcible way to drive up water by fire; not by drawing or sucking it upwards, for that must be as the philosopher calleth it, intra sphæram activitatis, which is but at such a distance. But this way hath no bounder, if the vessel be strong enough: for I have taken a piece of whole cannon, whereof the end was burst, and filled it three-quarters full of water, stopping and screwing up the broken end as also the touch-hole; and making a constant fire under it, within twenty-four hours it burst and made a great crack; so that having a way to make my vessels so that they are strengthened by the force within them, and the one to fill after the other, I have seen the water run like a constant stream, forty feet high: one vessel of water rarefied by fire, driveth up forty of cold water; and a man that tends the work is but to turn two cocks, that one vessel of water being consumed, another begins to force and refill with cold water, and so successively; the fire being tended and kept constant, which the self-same person may likewise abundantly perform in the interim, between the necessity of turning the said cocks." The next name to be mentioned in connection with the progressive history of the invention of the steam-engine, is that of Denis Papin, a native of France, who, being banished from his country, was established Professor of Mathematics at the University of Marburg, by the Landgrave of Hesse. He first conceived the important idea of obtaining a moving power by means of a piston working in a cylinder (1688), and subsequently (1690) that of producing a vacuum in the cylinder by the sudden condensation of steam by cold. In accordance with these ideas he constructed a model consisting of a small cylinder, in which was inserted a solid piston, and beneath this a small quantity of water; on applying heat to the bottom of the cylinder, steam was generated, the elastic force of which raised the piston; the cylinder was then cooled by removing the fire, when the steam condensed and became again converted into water, thus creating a vacuum in the cylinder, into which the piston was forced by the pressure of the atmosphere; there is, however, no evidence of his having carried |