DIFFERENT KINDS OF SHIPS. 87 



neath. The cylinder A is surrounded by a jacket, A', in order to prevent 

 the cooling of the steam. A constant body of steam circulates around the 

 cylinder, passing off' as it becomes condensed into water. The upper cap of 

 the cylinder A* has a lubricator, 5. In the steam cylinder is the piston, F, 

 with the metallic casing, F', and at the piston head, G' [C], a connecting-rod 

 [B] passes to the working-beam G [E'], and moves it up and down on its 

 pivot, / [E]. The cross-piece I [D] is attached to the first connecting-rod, 

 moving the lever HA in the different positions T and P, to which is hung the 

 piston-rod, K, for the air-pump. At the other arm of G, in L [E"], is the con- 

 necting-rod, M [L], which, in the positions L' and L" of the working-beam G, 

 turns the crank gudgeon N [L], and thus puts in motion the axis of the paddle- 

 wheels O [M]. On the axis, O, is the eccentric, Q [M'], and also a 

 second eccentric in the opposite direction. This eccentric, Q [M'], acts 

 by a sliding rod, Q' [N], on the regulating lever, m [N'], with a movable 

 counterpoise, and by the regulating lever [P] on the sliding rod, J [J], 

 of the regulating valve, B, in the cylinder, B. PI. 19, Jigs. 19, 20, 21, shows 

 the position of the different regulating levers and valves for the admission 

 of steam over the piston ; and Jigs. 25, 26, 27, for the escape of the steam 

 into the condenser. The letters are the same as on the parts represented 

 in Jig. 1. On the working-beam G [E], at [F], is hung the sliding-rod%r 

 the piston-rod [Q] of the piston, R, of the hot- water pump, E, which 

 through the valve, R', raises the water from the condenser, D, through o' 

 to S, whence it returns through S' to the boiler. The piston-rod with 

 its head [G] passes through the stuffing-box, T. P is the frame of the 

 engine. 



The marine engine is fed from a boiler in the same manner as those 

 used on land. Steamships are furnished with from four to six boilers. 

 PI. 19, Jigs. 12-15, represents a common boiler, one belonging to the French 

 steamship Tancred. Fig. 12 is a front view ; Jig. 13, a transverse section ; 

 Jig. 14, a longitudinal section ; and^g". 15, a horizontal section. The same 

 letters in each of the figures refer to the same parts. A, A', A", are portions 

 of the boiler, which is heated by the grates, B. From these the flame passes 

 through the chamber, C, and the flues, D, which run in different directions 

 around the boiler, the smoke escaping by the chimney, F. The steam 

 collects in the chamber, G, whence it raises the valve, ejgg', and passes 

 through the pipe, J, as soon as it has sufficient force to raise the valve, I. 

 The pipe H is the steam-pipe which conducts the steam to the engine. 

 K is the man-hole for cleaning the boiler. The pipes, L, L', L", which are 

 shut by the cocks, M, communicate with the atmosphere by the pipe h. 

 The apparatus OPR is connected on one side with the cold-water pump, 

 and on the other side with the conducting pipes of the condenser, in order 

 to supply the boiler with water. Of late the tubular boilers, which have 

 heretofore been used only for locomotives, have been introduced success- 

 fully into steamships. Figs. 16-18 represent a tubular boiler for an engine 

 of 450 horse-power, belonging to the English frigate Phenix. Fig. 16 is 

 the front view and transverse section ; fg. 17, the longitudinal section ; 

 and ^^. 18, the view of one half from above. A is the water chamber ; 



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