xxii DESCRIPTION OF PLATES. 



PLATE XX. 



Fig. 255. A jet or vein of a fluid, passing through an orifice in a thin plate in 

 any direction, and contracted after its escape, in consequence of the lateral motions 

 of the particles which flow towards the stream, nearly in the directions of the lines 

 here drawn. P. 212. 



Fig. 256. A stream flowing through a short cylindrical 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. 213. 



Fig. 257. 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 through the 

 tube E. P. 213. 



Fig. 258. A siphon, through which a fluid runs from the higher vessel into the 

 lower one. P. 215. 



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 similar 

 horizontal pipe. P. 216. 



Fig. 260. Subterraneous cavities, with outlets in the form of siphons, through 

 which they do not begin to discharge any water till they are nearly full ; the lower 

 one will then continue to run till it be empty. In the mean time either of them may 

 keep up a constant stream by other passages. P. 217. 



Fig. 261. A tube turned up and contracted, so as to throw out the fluid con- 

 tained in it, in a jet, which rises very nearly to the height of the fluid in the tube. 

 P. 217. 



Fig. 262. The forms of jets issuing from various parts of a reservoir, the ampli- 

 tude A B being twice C D, and A E four times F G. P. 217. 



Fig. 263. A series of waves, moving in the direction A B, and reflected by the 

 obstacle B, lose the appearance of progressive motion, and vibrate up and down 

 within the limits of the curves A C D E B, and F G H I K ; the elevation and 

 depression become however twice as great as before reflection. P. 219. 



Fig. 264. 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 surface B C. P. 219. 



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. 220. 



Fig. 266. A series of waves, diverging from the centre A, and passing through 

 the aperture B C, extend themselves on each side so as to fill the space B C D E, 

 while they affect the parts without this space much less sensibly. P. 220, 360. 



Fig. 267. Two equal series of waves, diverging from the centres A and B, and 

 crossing each other in such a manner, that in the lines tending towards C, D, E, and 

 F, they counteract each other's effects, and the water remains nearly smooth, while 

 in the intermediate spaces it is agitated. P. 220, 364. 



