80 THE SEA. 



across the boat, and dipping into the water, so as to be turned by the wheels, would fulfil 

 the conditions proposed of advancing the boat faster, the more rapid the stream ; and when 

 at anchor such wheels might have been applied to the other purposes." Floating mills, 

 worked by large water-wheels, may be seen on the Rhine to-day. 



Papiu, the French philosopher, while in England, witnessed an experiment on the 

 Thames, in which a boat, fitted with revolving oars or paddles, was worked from a kind 

 of treadmill turned round by horses. " The velocity with which this horse-boat was 

 impelled was so great, that it left the king's barge, manned with sixteen rowers, far 

 astern in the race of trial." In 1682, a horse tow vessel was used at Chatham. It was 

 " constructed with a wheel on each side of the vessel, connected by an axle going across 

 the boat, and the paddles were made to revolve by horses moving a wheel turned by a 

 trundle fixed on the axle. It drew but four and a half feet of water, and towed the 

 greatest ships by the help of four, six, or eight horses." 



In 1729, Dr. John Allen obtained a patent for his new invention, one which has been 

 revived with some success in later days. It was to propel a vessel by forcing water 

 through the stern, at a convenient distance under the surface of the water, into the sea, 

 by suitable engines on board. "Amongst," says the doctor, "the several and various 

 engines I have invented for this purpose, is one of a very extraordinary nature, whose 

 operation is owing to the explosion of gunpowder, 1 having found out a method of firing 

 gunpowder in vacuo, or in a confined space, whereby I can apply the whole force of it, 

 which is inconceivably great, so as to communicate motion to a great variety of engines, 

 which may also be applied in working mines and other purposes." And again, in 17GO, 

 a Swiss clergyman published a pamphlet in London, in which oars worked with springs 

 were to be used, and the expansive power of gunpowder was to be used to bend the 

 springs. He states, candidly enough, that since he arrived in England he had learned 

 that thirty years before a Scotchman had proposed to make a ship proceed by means of 

 gunpowder, but that thirty barrels had scarcely forwarded it ten miles. We may smilo 

 at these attempted uses of gunpowder, but they were doubtless suggested by the scientific 

 studies of the day, which were particularly directed to the expansive power of vaporised 

 water. In our own day, steam has been substituted for powder in discharging a cannon. 

 Perkins' " steam-gun" was long one of the curiosities of the Polytechnic Institution. 



On the 5th of January, 1769, James Watt obtained a patent for a series of 

 improvements in the steam-engine, one of which was most important in its bearing on 

 naval engines. It was that which provided for steam acting above the piston as well 

 as below it, in, of course, the same cylinder. Here was a grand move at once. Previously 

 every engine for pumping, the only practical purpose to which steam was yet put, was 

 worked by a beam engine and pair of cylinders. In 1779, Matthew Wasborough, an 

 engineer of Bristol, obtained a patent, as others, indeed, had before him, for converting 

 a rectilinear into a continuous circular motion. It failed, as the others had done, because 

 they required ratchet wheels, pulleys, &c. The following year James Pickard invented the 

 present connecting-rod and crank, with fly-wheel, and removed the great obstacle to 

 propelling vessels by steam. The following year, again, Watt invented what is now 

 known as the " sun and planet motion," another step in the same direction. 



