HYDRAULICS. 225 



In describing the effects produced by steam 

 engines, the work performed by a horse is generally 

 made use of as a standard; accordingly we say an 

 engine of 10, 20, 30, &c. horse power. A steam 

 engine having a cylinder of 19 inches diameter, 

 making 25 strokes of 4 feet per minute, and con- 

 suming 3700 pounds of coals per day, is equivalent 

 in power to 20 horses. A cylinder of 24 inches, 

 making 22 strokes of 5 feet, and burning 5500 

 pounds of coals, is equal to 20 horses. 



STEAM BOATS. 



Among the numerous applications of steam is 

 that of propelling vessels by it, without the aid of 

 sails or oars. 



It appears that, as long ago as 1736, one Jonathan 

 Hulls, of London, took out a patent for a method 

 of moving vessels on the water by machinery 

 worked by a steam engine. But although several 

 others since that time made several experiments 

 with steam boats, yet Fulton was the first who suc- 

 ceeded in applying them on an extensive scale, 

 which he did upon the great lakes in North 

 America about 1808. In 1813, the steam boat 

 was first introduced into this country upon the 

 river Clyde. 



The hull of the steam vessel is not very different 

 in form from that of a ship constructed for sails, 

 but has no rigging or upper works. About the 

 middle of the vessel is fixed the boiler of the steam 

 engine, which is made to work a wheel on each 

 side of the vessel, nearly similar to the wheel of an 

 undershot mill, by the action of which on the water 

 the vessel is moved. The smoke from the boiler fur- 

 nace is carried off by an iron flue of considerable 



vol. 1. Q 



