Dr. Desaguliers, we conceive, ungenerously attacked Captain Savery’s reputation, by alleging that this was not an original invention, and that he was indebted for the first idea to the previously mentioned plan of the Marquis of Worcester. Dr. Rees, with a generous liberality worthy his great critical discrimination, scientific skill, and general erudition, has, we think, ably defended the captain’s character, by proving his ideas to have originated with himself; we have only an opportunity to notice the most prominent features in this justification, where Dr. Rees thus expresses himself. “We know that the Marquis of Worcester gave no hint concerning the _contractibility or condensation of steam, upon which all the merit of the modern engine depends_. The Marquis of Worcester’s engine was actuated wholly by the elastic power of steam, which he either found out, or proved by the bursting of cannon in part filled with water; and not the least hint that steam so expanded, is capable of being so far contracted in an instant, as to leave the space it occupied in a vessel, and occasion, in a great measure, a vacuum.” Subsequent to the Marquis of Worcester’s, and Captain Savery’s original ideas, and also, subsequent to the perfection the captain had brought his machine to, M. Amonton, a native of France, invented a machine which he called a fire-wheel; but it does not appear that it was ever brought to that perfection to be conducive to real utility, although it was certainly very ingenious. Also, M. Papin, a native of Germany, made some pretensions to what he alleged was an invention of his own, only it happened to appear, unfortunately for his claim, that he was in London, and present at the time when Captain Savery exhibited the model of his steam-engine to the Royal Society. He made some unsuccessful experiments, by order of his patron, the Landgrave of Hesse, which sufficiently proved that, if he was the inventor, he did not understand the nature of his own machine. Not long after Savery had invented his engine, Thomas Newcomen, an ironmonger, and John Calley, a glazier, began to direct their attention to the employment of steam as a mechanic power. Their first engine was constructed about the year 1711. This machine still acted on the principle of condensing the steam by means of cold water, and the pressure of the atmosphere on the piston. It was found of great value in pumping water from deep mines; but the mode of its construction, the great waste of fuel, the continued cooling and heating of the cylinder, and the limited capacities of the atmosphere in impelling the piston downward, all tended to circumscribe its utility.