xviii CONTENTS. 



PART THE SECOND. HYDRODYNAMICS. 



LECTURE XXI. 

 ON HYDROSTATICS, 195. 



Hydrodynamics more dependent on experiment than mechanics ; Division of 

 the subject into Hydraulics, Acustics, and Optics, 195. Hydrostatics ; Definition 

 of a fluid and a liquid, 196. Surface of a gravitating fluid horizontal, 197. Sur- 

 face of a revolving fluid ; Pressure of a fluid ; Magnitude of hydrostatic pressure, 

 198. Hydrostatic paradox, 199. Blowing with the mouth and lungs ; Pressure 

 on the bank of a river ; Pressure on a concave surface, 200. Pressure of different 

 fluids ; Equilibrium of fluids with solids; Floating bodies, 201. Stability and os- 

 cillations of floating bodies ; Buoyancy, 202. Bodies falling in fluids ; Hooke's 

 hemisphere ; Flexible vessels, 203. 



LECTURE XXII. 

 ON PNEUMATIC EQUILIBRIUM, 204. 



Properties of the air, and of gases ; Mercurial column, 204. Steams and vapours ; 

 Weight of the air ; Experiments with the air pump, 205. Constitution of the at- 

 mosphere ; Measurement of heights ; Ascent of a balloon, 206. Pressure of the 

 atmosphere ; Magdeburg hemispheres ; Nature of suction, 207. Barometers, 208. 

 Compressibility of liquids, 209. 



LECTURE XXIII. 

 ON THE THEORY OF HYDRAULICS, 210. 



General principle of ascending force, 210. Bernoulli's inferences ; Velocity 

 of a jet of a fluid, 211. Ajutages of different kinds ; Contraction of a jet, 212. 

 Effect of a short pipe ; Diverging pipe ; Experiments of Bernoulli, Venturi, and 

 Matthew Young; Discharge through large apertures, 213. Vessels emptying 

 themselves ; Locks, 214. Siphons ; Discharge through a vertical pipe, 215. Ex- 

 planation; Limit of velocity; Whirlpool; Intermitting springs, 216. Ascending 

 jets; Oscillations of fluids, 217. Waves, 218. Reflection of waves ; Height of 

 waves ; Experimental exhibition of waves, 219. Divergence of waves ; Combina- 

 tions of waves ; Applications ; Elastic pipes ; Circulation of the blood, 220. 



LECTURE XXIV. 



ON THE FRICTION OF FLUIDS, 222. 



Experiments of Du Buat ; Motions of rivers ; Friction and resistance, 222. 

 Examples of the velocity of rivers, 223. Velocity at different depths ; Weres, 224. 

 Changes and flexures of rivers ; Lateral friction ; Venturi's experiments, 225. Ball 

 supported by a jet ; Discharge of long pipes, 226. Bent pipes ; Dilatations of 

 pipes ; Effect of temperature, 227. 



