OF STEAM ENGINES. 175 



is now forming for the express purpose of facilitating the convey- LECT. 

 ance of goods by locomotive engines. 



The mode of applying the steam engine to the purposes of v " 

 navigation is equally simple with its employment in our manu- 

 factures. 



It is generally supposed that the steam-boat is of very recent 

 invention ; on the contrary, however, the possibility of employing 

 steam as a prime mover in the propelling of vessels, was sug- 

 gested as far back as the reign of Charles I. 



In one of the old tracts preserved in the library of the London 

 Institution there is a very curious representation of a steam boat, 

 constructed by an engineer of the name of Hulls. And this indi- 

 vidual, now so little known, was undoubtedly the first who applied 

 a steam engine to the purpose of na^ igation. 



To impel a vessel by this means, two paddle wheels, like those 

 used in an under-shot water wheel, are connected by means of a 

 long axis and crank, with the working beam of the steam engine ; 

 and if this motion is not found sufficiently rapid, a wheel and 

 pinion are added, which, although it decreases the effective power 

 of the engine, yet increases the velocity of the paddle wheels. 



To illustrate the great advantages possessed by the steam 

 engine, even in its rudest state, over every other species of prime 

 mover yet enumerated, it may now be advisable to examine its 

 effective force when employed in the working of pumps. It 

 has been found that one hundred weight of coals burned in an 

 engine on the old construction, would raise at least twenty thou- 

 sand cubic feet of water twenty-four feet high ; an engine with 

 a twenty-four inch cylinder doing the work of seventy-four 

 horses. An engine on Capt. Savery's plan, constructed by 

 Mr. Keir, has been found to raise nearly three millions of 

 pounds of water, and Mr. "Watt's engine, upwards of thirty 

 millions of pounds the same height.* 1 



To the mining interests this valuable present of science to the 

 arts has been peculiarly acceptable ; as a large portion of our 



Note 51. An ingenious foreigner, who lately visited England, has 

 published an estimate of the mechanical force set in action by the 

 steam engines of this country. 



He supposes that the great pyramid of Egypt required for its erec- 

 tion the labour of more than 10,000 men for 20 years : but if it were 

 required again to raise the stones from the quarries, and place them 

 at their present height, the action of the steam engines of England, 

 which are managed at most by 36,000 men, would be sufficient to 

 produce the same effect in 18 hours. 



