His invention, however, did not answer, and was indeed superseded by that of James Pickard, 23rd August, 1780, who, shortly afterwards entering into partnership with Wasborough, patented a method of working a mill with a rotary motion by means of the present connecting rod and crank and a fly wheel, constituting the second important improvement in the steam-engine, and enabling it to be of really practical service in propelling vessels. In 1781 (25th October), James Watt obtained another patent for his newly invented method of applying the vibrating or reciprocating motion of steam or fire-engines to procure a continued circular motion round an axis so as to turn the wheels of mills or other machines. This invention is known as the “Sun and Planet” motion.[49]
Marquis de Jouffroy.
In the same year (1781), the Marquis de Jouffroy is said to have constructed a steam-boat at Lyons 140 feet in length, and to have made with her several successful experiments on the Saone near that city. Mr. MacGregor, however, has made particular inquiries[50] into the authenticity of the claims of the Marquis, and, as no description of the machinery of this vessel is discoverable earlier than that given by himself thirty years afterwards, when he petitioned for the use exclusively of steam-boats for fifteen years, these claims are, to say the least, very questionable, while, in a report on his improvements, the invention is said to be Rumsey’s, but more likely that of his own countryman Gauthier, whose death prevented his plans from being practically exemplified by the Venetian Republic. The French Revolution, however, supervening, the Marquis had not an opportunity of prosecuting his undertaking.
Bramah’s screw-propeller.
In 1785, Joseph Bramah, a man of great genius, and the inventor of the hydraulic press, obtained a patent for an hydrostatical machine and a boiler on a peculiar principle, in which the power of air, steam, or any other elastic vapour, might be employed for the working of engines. Another of his inventions is a mode of propelling vessels by the improved rotatory engine described in the specification, through the medium of either a paddle-wheel or what may be called a screw-propeller. Bramah shows a vessel with a rudder placed in the bow, and describes in his specification the nature of the “screw-propeller” and of its mode of action in minute and specific terms.[51]
Although there is no record of Bramah having put his proposal into practice, the description lodged by him at the Patent Office is interesting, as showing clearly an indication of the now so well-known screw-propeller. Moreover, in this invention, he obviously intended that steam should be used so as to give circular motion to the propeller shaft. Previously, however, to the time when he patented his invention, the rotatory screw as a mode of propulsion had been proposed by Watt, who, in 1770, suggested the application of a screw-propeller to be turned by a steam-engine.[52]
But more than half a century elapsed before the screw, now in almost general use, was practically applied; indeed, the first authentic record we possess of the marine engine itself having been successfully worked by paddle or any other means on board any vessel, dates no further back than 1787, although, between 1774 and 1790, Fitch and Rumsey were experimenting in America on boats (to which I shall hereafter refer) to work against streams.
Mr. Miller of Dalswinton.
In that year (1787) Mr. Patrick Miller, of Dalswinton in Scotland, a gentleman of position and fortune, published a pamphlet (given at length by Mr. Woodcroft[53] in his interesting and instructive work on steam navigation, with copies of Mr. Miller’s drawings illustrative of his scheme), on the subject of propelling boats by means of paddle-wheels turned by men, working on a capstan with five bars, each 5 feet long, which drove a water-wheel, having the same object in view as Messrs. Fitch and Rumsey, then engaged on similar works on the other side of the Atlantic.
This wheel, of which the following is a sketch, drove the vessel in a calm from 3 to 4 miles an hour; and, as Mr. Miller judged the capstan the best mode of turning the wheel, he rejected for a time all other modes, believing manual labour so applied more to be depended on than any mechanical contrivances. For the purpose of his experiments he built, from first to last, eight boats of different kinds, expending no less than 30,000l. on them and their machinery. One was a treble vessel, or rather three boats fastened together, of which the following is a transverse representation of the fore part with the lower floats of the wheels at their full dip.