(30.) The discovery of the method of making a vacuum by the condensation of steam was reproduced, before 1698, by Captain Thomas Savery, to whom a patent was granted in that year for a steam engine to be applied to the raising of water, &c. Savery proposed to combine the machine described by the Marquis of Worcester with an apparatus for raising water by suction into a vacuum produced by the condensation of steam. Savery appears to have been ignorant of the publication of Papin, and stated that his discovery of the condensing principle arose from the following circumstance:— Having drunk a flask of Florence at a tavern, and flung the empty flask on the fire, he called for a basin of water to wash his hands. A small quantity which remained in the flask began to boil, and steam issued from its mouth. It occurred to him to try what effect would be produced by inverting the flask and plunging its mouth in the cold water. Putting on a thick glove to defend his hand from the heat, he seized the [Pg048] flask, and the moment he plunged its mouth in the water the liquid immediately rushed up into the flask and filled it. Savery stated that this circumstance immediately suggested to him the possibility of giving effect to the atmospheric pressure by creating a vacuum in this manner. He thought that if, instead of exhausting the barrel of a pump by the usual laborious method of a piston and sucker, it was exhausted by first filling it with steam, and then condensing the same steam, the atmospheric pressure would force the water from the well into the pump-barrel, and into any vessel connected with it, provided that vessel were not more than about thirty-four feet above the elevation of the water in the well. He perceived also, that, having lifted the water to this height, he might use the elastic force of steam in the manner described by the Marquis of Worcester to raise the same water to a still greater elevation, and that the same steam which accomplished this mechanical effect would serve, by its subsequent condensation, to reproduce the vacuum, and draw up more water. It was on this principle that Savery constructed the first engine in which steam was ever brought into practical operation. [Illustration: BRANCA'S ENGINE.] FOOTNOTES: [1] Arago, Eloge historique de James Watt; p. 22. [2] Ibid., p. 21. note. [3] Farey, Treatise on the Steam Engine, p. 93. [4] Arago, sur les Machines à Vapeur, Annuaire, 1829, p. 165 [5] SPIRITUS, _breath_ or _air_. [6] Exactly 15·68 oz. = 0·98 lb. [7] This experiment with the tube A requires to be very carefully executed, and the tube should be one of small bore. [8] Recueil de diverses Pièces touchant quelques nouvelles Machines, p. 38. [Pg049] [Illustration: SAVERY'S ENGINE.] CHAP. II. ENGINES OF SAVERY AND NEWCOMEN.