xx CONTENTS. 



Velocity of a blast, 263. Ventilation ; Corn fan, 264. Chimnies ; Furnaces ; 

 Balloons; Steam engines; Savery's engine, 265. Newcomen's arid Beighton's 

 engine ; Watt's improvements, 266. Power of Boulton and Watt's machines ; 

 Later alterations, 267. Gunpowder; Calculations of Bernoulli and of Count 

 Rumford ; Properties of a gun ; Bullets ; Shot, 268. Air gun ; Improvements 

 on steam engines ; Stray Park engine ; Cornish boiler, 269. D valve, 270. Ap- 

 plication of steam engine to navigation ; G. Dodd ; Explanations ; Marine engines, 

 271. High pressure engine ; Young's formula for the elasticity of steam; For- 

 mula of the Franklin Institute ; Trevithick, 272. Description of the locomotive 

 engine, 272, 273, 274-, 275. 



LECTURE XXX. 

 ON THE HISTORY OF HYDRAULICS AND PNEUMATICS, 275. 



Discoveries of Archimedes ; Ctesibius; Hero; Vitruvius, 276. Canals; Gun- 

 powder; Galileo; Torricelli; Castelli, 277. Mariotte; Guglielmini; Guericke; 

 Hooke ; Marquis of Worcester, 278. Huygens ; Pardies : Renaud ; James and 

 John Bernoulli ; Newton, 279. Poleni ; Bouguer ; D. Bernoulli, 280. John 

 Bernoulli; Maclaurin ; Robins, 281. Dalembert; Kaestner; Euler; Smeaton ; 

 Borda; Watt, 282. Specification of Mr. Watt's patent, 282, 283. Bossut; Juan; 

 Prony; Chapman; Romme; Hutton; Rumford, 284. DuBuat; Black; Mont- 

 golfier, 285. Chronological table, 286. 



LECTURE XXXI. 



ON THE PROPAGATION OF SOUND, 287. 



Importance of acustics; Division of the subject; Definition of sound; Pro- 

 pagation of sound, 287. Velocity of sound ; Delineation of a sound, 288. Com- 

 pressibility of hard bodies ; Transmission of sound by different mediums, 289. 

 Correction on account of heat, 290. Transmission in gases of different kinds ; In 

 liquids; In solids, 291. Divergence of sound, 292. Reflection of sound ; Illus- 

 tration by waves of water; Speaking trumpet, 293. Whispering gallery; Invisible 

 girl ; Partial interception of sound ; Decay of sound, 294. 



LECTURE XXXII. 



ON THE SOURCES AND EFFECTS OF SOUND, 295. 



Origin of a simple sound; Of a continued sound; Musical sounds derived 

 from vibrations, 295. Open pipes; Stopped pipes; Harmonic sounds, 296. 

 Effect of temperature ; Longitudinal sounds of solids ; Lateral vibrations ; Flexi- 

 ble cords and membranes, 297. Harmonic sounds of cords, 298. Loaded 

 wire ; Revolutions of cords ; Vibrations of elastic rods, 299. Vibrations of 

 plates, rings, and vessels, 300. Mixed vibrations of solids and fluids ; Sympa- 

 thetic sounds; Hearing, 301. Description of the ear, 302. Delicacy of the 

 ear, 30a 



