[48] There seems little doubt (see Lardner, p. 186, and Muirhead’s “Life of Watt,” p. 273), that Watt was the real inventor of the crank for which Mr. Wasborough obtained the credit. Mr. Watt says distinctly, that, having noticed, in 1778 or 1779, certain defects in the “ratchet wheels” invented by Wasborough, he proceeded to remedy them, but having neglected to take out a patent for these improvements, a workman employed to make Mr. Watt’s model told “some of the people about Mr. Wasborough,” on which he took a patent for the application of the crank to steam-engines.
[49] In the Patent Museum, London, may be seen now (1875), the same “Sun and Planet” engine (a great curiosity), which Watt constructed in 1788 at Soho, near Birmingham.
[50] See “Specifications relating to Marine Propulsion” (Part II.), p. 109, in which the existing documents are recapitulated and described.
[51] There is more in Bramah’s inventions than at first appears, and the scientific reader would do well to study that part of them referring to the “boiler.” The following remarks have reference to the screw:—
“Instead of the (paddle-wheel) A, may be introduced a wheel with inclined fans or wings, similar to the fly of a smoke-jack, or the vertical sails of a windmill: this wheel or fly may be fixed on the spindle C alone, and may be wholly under water, where it would, by being turned round either way, cause the ship to be forced backwards or forwards, as the inclination of the fans or wings will act as oars with equal force both ways, and their power will be in proportion to the size and velocity of the wheel; allowing the fans to have a proper inclination, the steam-engine will also serve to clear the ship of water with singular expedition, which is a circumstance of much importance. This “apparatus for working the ship” is fixed in or beyond the stern, in or about the place where the rudder is usually placed, and its movement is occasioned by means of an horizontal spindle or axletree conveyed to the engine through the stern end of the ship.”
[52] See letter to Dr. Small (who replies he had tried it); Muirhead’s “James Watt,” London, 1854, vol. ii. pp. 4, 8, 11.
[53] “Woodcroft on Steam Navigation,” p. 20, et seq.
[54] “Specifications relating to Marine Propulsion,” Part I. p. 36.
[55] It is clear that Mr. Symington is entitled to the credit of the application of steam-power to propel the paddles. Mr. Miller stuck to the capstan and manual labour, but, on one occasion, having been to see Symington’s locomotive, he told him of his own invention, and of the difficulty he had with his paddles for lack of power. “Why don’t you use the steam-engine?” was Symington’s immediate remark. Miller at once assented, but first constructed a double vessel, with the paddle-wheels worked by five men at the capstan amidships, and, in June 1787, the first experiment with her was deemed successful. A short time subsequently steam was directly applied, but, whether in consequence of Symington’s remark, is not certain. Mr. Taylor, who is said to have suggested it, was an intimate friend and fellow-pupil with Symington at Edinburgh 1786-7. (Smiles’ “Lives of Boulton and Watt,” p. 438.)
[56] Dumfries paper; Edinburgh Advertiser, and the Scot’s Magazine, vol. 1. p. 566, November, 1788.