Another advantage which this engine has over those of Savery, is the facility with which it might be applied to drive machinery by means of the working beam. The merit of this engine as an invention, must be ascribed principally to its mechanism and combinations. We find in it no new principle; the agency of atmospheric pressure acting against a vacuum, or a partial vacuum, was long known. The formation of a vacuum by the condensation of steam had been suggested by Papin and Savery, and carried into practical effect by the latter. The mechanical power derivable from the direct pressure of the elastic force of steam was distinctly pointed out by Lord Worcester, and even prior to his time; the boiler, gauge-pipes, and regulator of the atmospheric engine, were evidently borrowed from Savery's engine. The idea of working a piston in a cylinder by the atmospheric pressure against a vacuum below, was suggested by Otto Guericke, an ingenious German philosopher, the inventor of the air-pump, and subsequently by Papin; and the use of a working beam could not have been unknown. Nevertheless, considerable credit must be acknowledged to be due to Newcomen for the judicious combination of those scattered principles. "The mechanism contrived by him," says Tredgold, "produces all the difference between an efficient and inefficient engine, and should be more highly valued than the fortuitous discovery of a new principle." The rapid condensation of steam by the injection of water, the method of clearing the cylinder of air and water after the stroke, are two contrivances not before in use, and which are quite essential to the effective operation of the engine: these are wholly due to Newcomen and his associates. (44.) The patent of Newcomen was granted in 1705; and in 1707, Papin published a work, entitled "A New Method of raising Water by Fire," in which a steam engine is described, which would scarcely merit notice here but for the contests which have arisen upon the claims of different nations for a share in the invention of the steam engine. The publication of this work of Papin was nine years after Savery's patent, with which he acknowledges himself acquainted, and two years after Newcomen's. The following is a description of Papin's steam engine:--