487. 



The steam ship is one of the 

 greatest triumphs of modern 

 science. The principle of the 

 engine by which the vessel is 

 propelled, is precisely the same 

 as in the stationary engine, 380, 

 and in the locomotive, 442. The 

 triumph achieved by the steam 

 ship is greater than that by the 

 locomotive, because in the latter 

 the difficulty which had to be 

 conquered was chiefly the appli- 

 cation of steam machinery to 

 overcome the inertia or tendency 

 of bodies to remain at rest. But 

 the ship is liable to opposing 

 forces of wind and water, and 

 these are constantly varying in 

 their strength and direction. Yet 

 the steam ship rides proudly in 

 defiance of the opposing elements, 

 and voyages by steam are now 

 effected to the extreme parts of 



the world, although, when the 

 steam vessel was first proposed, it 

 was regarded as merely a means 

 for towing ships in and out ot 

 harbours. 



The construction of the boilers 

 is varied in vessels of different 

 dimensions ; sometimes they are 

 made square, at other times cylin- 

 drical, and in some cases to suit 

 the shape of the vessel. The fire 

 circulates through flues, which 

 pass several times from one end 

 of the boiler to the other, in 

 order that as much heat as 

 possible may be given out before 

 the flame and smoke arrive at 

 the funnel. 



The furnaces and boilers are 

 situated some distance from the 

 engines, and the steam passes 

 from the steam chamber to the 

 cylinders by the steam pipes. 



