780 



PLATE XXIII. 



Fig. SD4. A centrifugal pump. The machine is 

 first filled through tlie fuiuiel A, and when it is made 

 to revolve, the water is discharged into a circular 

 trough, of which a section is seen at B and C. The 

 valve at U remains shut while the pump is filling. P. 

 331. 



Fig. 303. A pump consisting of two plungers, con- 

 tinued nearly to the height at which the water is de- 

 livered. P. 332. 



Fig. 306. Lahire's double forcing pump. When 

 the piston is depressed, the water enters the barrel at 

 the valve A, and goes out at B; when it is elevated, it 

 enters at C and escapes at D. P. 332. 



Fig. 307. The common piston, coated with leather. 

 P. 332. 



Fig. 308. Mr. Bramah's press. The pump A forces 

 tlie water throngh the jiipe B into the barrel C, in 

 which it acts very powerfully on the large piston D, 

 and raises tlie bottom of the press E. P. 332. 



Fig. 309. Tlie common sucking pum)). P. 333. 



Fig. 310. A bag pump, the bag or pufl" A being ex- 

 tended and contracted by the motion of the piston. 

 P. 333. 



Fig. 311. A lifting pump, the piston rod A B being 

 drawn up by a frame. P. 333. 



Fig. 312. A sucking pump, converted, by the addi- 

 tion of a collar of leathers at A, into a forcing pump. 

 P. 333. 



F'ig. 313. A fire engine, on a construction similar to 

 some machines described by Raiuclli. A B is the pis- 

 ton, working within a cylindrical barrel, and moved 

 by the handles C 1). When the end C is depressed, 

 the water enters through the valves E and F, and is 

 discharged at O and II ; when D is depressed, the wa- 

 ter enters at I and K, and is discharged at L and M, 

 into the air vessel N, whence it is expelled by the pipe 

 O. The pipes P and Q may be united, if it be re- 

 quired. P. 334. 



Fig. 314. I'rom Ramelli. The wheel A B, revolving 

 in the direction B A, carries a portion of water C be- 

 tween itself and the sweep D F,, which ii intercepted 

 by the shder F, and forced up the pipe FG. P. 335. 



Fig. 815. From Ramelli. The roller A, revolving 

 within the reservoir B C, which is nearly cylindrical, 

 carries with it the slider D E, which is wade to sweep 



the internal surface of the cylinder from C to F, by 

 means of a projecting surface acting on the end D, so 

 that the water G is forced through the pipe F. P. 335. 



Fig. 316. From the cabinet of jMr. Serviere. The 

 wheels A and B carry, during their revolution, a quan- 

 tity of water from C to D, or from D to C, according 

 to the direction in which they are turned. P. 335. 



Fig. 317. Mr. Gwynu's patent water engine. The 

 valve A is kept, partly by means of the spring B, bat 

 still more by the pressure of the water, in contact with 

 the roller or piston C, which revolves within the box 

 J) E, and sweeps it from E to F, so that the portion 

 of water G is forced, during each half of a revolution, 

 into the pipe F; or is drawn from F to E, when the 

 roller revolves in a contrary direction. P. 335. 



F'ig. 318. A chain pump. P. 335. 



F'ig. 319. The mechanism of Hull's acting pump. 

 In the position of the stopcock A B, here represented, 

 the water flows out of the barrel C, and the piston 1> 

 is allowed to descend. The rod E then turns the 

 stopcock, and the barrel C communicates only with 

 the pipe F, which fills it, and forces up the piston, 

 until the stopcock is turned back to its former posi- 

 tion. P. 336. * 



t Fig. 320. The hydraulic air vessels of Schcranit2. 

 The reservoir A being filled with water, and B with 

 . air, and water being poured into the funnel C, the air 

 in B acts by the pipe D on the water in A, and forces 

 it up the pipe E. P. 337. 



Fig. 321. A being the high water mark, and B the 

 low water mark, the vessels C and D are filled at high 

 water from below, the air being suft'ercd to escape by a 

 stopcock, which is opened by the fall of the ball F ; at 

 low water the air will enter the vessel D at B ; and be- 

 fore the next high water, the water C will be forced up 

 the pipe E. P. 337. 



i'ig. 322. The fountain of Hero. Its operation re- 

 sembles that of the hydraulic air vessels, fig. 320; but 

 the pipe D here ascends. P. 337. 



Fig. 323. The hydraulic ram of Montgolfier. When 

 the w ater in the pipe A B has acquired a sufficient ve- 

 locity, it raises the valve B, which stops its passage, 

 so that a part of it is forced through the valve C, into 

 the air vessel D, whence it rises through the pipe E, 

 P. 338. 



