STEAM ENGINE. 55 



dtvers are generally let down from a ship, and taking a rope 

 with them, to which is fixed a bell in the vessel, they have 

 only to pull the string, and the people in the ship draw them 

 up ; but if business requires it, they will stay several hours 

 at the bottom of the sea without the smallest difficulty. By 

 means of a strong globular cap with circular glasses in front 

 to give light, it has been found practicable for a diver to go 

 out of the engine to the distance of eighty or a hundred 

 yards, the air being conveyed to him in a continued stream 

 by small flexible pipes. Accidents, which through careless-* 

 ness have sometimes occurred, may be readily prevented, by 

 a proper degree of attention, and people may descend to very 

 great depths without danger. The diving bell has often 

 been used in bringing up the goods from a vessel which has 

 sunk in deep water, and in blowing rocks which impeded 

 navigation. 



The Steam Engine is one of the most useful, curious, and 

 important machines that have ever been invented. It con- 

 sists of a large cylinder or barrel, in which is fitted a solid 

 piston like that of the forcing pump. Steam is supplied from 

 a large boiler, which in forcing up the piston, instantly opens 

 a valve, through which cold water rushes, on the principle 

 of the common pump. Other steam is then introduced 

 above the piston, which forces it down, and drives the water 

 out of the pipe. Steam raises the piston again, and agai;: 

 makes it fall, and thus produces an alternate motion, which 

 is communicated, by an upright iron rod, to a large beam or 

 lever, that is lifted up and pulled down with wonderful pre- 

 cision and force. This regular and powerful motion is easily 

 applied by the mechanic to all kinds of machinery. The 

 apparatus has been varied by diflferent persons, and for diffe- 

 rent objects ; but the principle remains the same. 



By the admirable contrivances of Watt and Fulton, the 

 steam-engine has become a thing stupendous alike for its 

 force and flexibility, — for the prodigious power which it can 

 exert, and the ease, and precision, and ductility with which 

 it can be varied, distributed, and applied. The trunk of an 

 elephant, that can pick up a pin or rend an oak, is nothing 

 to it. It can engrave a seal, and crush masses of obdurate 

 metal before it,— draw out, without breakings a thread as 

 fine as gossamer, and lift up a ship of war like a bauble in 

 the air. It can embroider muslin and forge anchors, — cut 



