777 



PLATE XX. 



Fig. 255. A jet or vein of a fluid, passing through an 

 orifice in a tl)in plate in any direction, and contracted 

 after its escape, in consequence of tlie lateral motions 

 of the particles which flow towards the stream, nearly 

 in the directions of the lines here drawn. P. HBO. 



Fig. 256. A stream flowing through a short cylin- 

 drical pipe, compared with another flowing through a 

 diverging conical pipe, the directions of the motions 

 of the particles appearing to be nearly similar in both 

 cases. P. 281. , ■ : 



Fig. SST. In an experiment of D, Bernoulli, the 

 water flowing through the conical pipe A drew up 

 water through the tube B from the vessel C ; in another 

 of Venturi, the water flowing through the cylindrical 

 pipe D raised water througli the tube E. P. 281. 

 , Fig. 258. A siphon, through which a fluid rnns 

 from the higher vessel into the lower one. P. 283. 



Fig. 259. A fluid flowing through a vertical pipe, 

 and filling a vessel to a height nearly equal to the 

 length of the pipes, while it is discharged through a si- 

 milar horizontal pipe. P. 284. 



Fig. 260. Subterraneous cavities, with outlets in 

 tlie form of siphons, through which they do not begin 

 to discharge auy waliT till they are nearly full; tlie 

 lower one will then continue to nui liU it be empty. 

 In the mean time either of them may keep up a con- 

 stant stream by other passages. P. 285- 



Fig. 261. A tube turned up and Contracted, sn as 

 to throw out the fluid contaiurd in it, in a jet, which 

 rises very nearly to the height of the fluid in tlic tube. 

 P. 286. 



Fig. 262. The forms of jets issuing from various 

 parts of a reservoir, tlie amplitude A B being twice 

 C D, and AE four times F G. P. 280. 



Fig. 263. A series of waves, moving in the direc- 

 tion A B, and reflected by the obstacle B, loses the 

 appearance of pi'ogrcssive motion, and vibrates up and 

 down within the limits of the curves A C D E B, and 

 F G II I K ; the elevation and depression become 

 however twice as gieat as before reflection. P. 289> 



Fig. 26-1. A series of waves diverging from a centre 

 A, and striking a fixed obstacle B C, are reflected by it 

 into the same form as if they proceeded from the centre 

 D, at an equal distance on the opposite side of the sur- 

 face BC. P^2«9. 



Fig. 265. An apparatus for observing the motions 

 of waves excited, in a fluid poured into the trough 

 A B, by the vibrations of the elastic wire C, loaded 

 with a moveable weight D; the shadow of the waves 

 being thrown on a screen E by the lamp F, through 

 the bottom of the trough, which is of glass. P. 290; 



Fig. 2CC. A series of waves, diverging from the 

 centre A, and passing through the aperture BC, ex- 

 tend themselves on each side so as to fill the space 

 BCDE, while they alTect the parts without thi» 

 space much less sensibly. P. 290, 458. 



Fig. 267. Two equal series of waves, diverging from 

 the centres A and B, and crossing eaeh other in sucii 

 a manner, that in the lines tending towards C,D,E, 

 and F, they counteract each other's cflVcts, and tlie 

 water remains nearly smooth, while in the interme- 

 diate spaces it is agitated. P. 290, 461. 



