234 LECTURE XXV. 



have attained by the mere hydrostatic pressure of the water at a depth so 

 inconsiderable. But a more powerful cause than this appears to be the* 

 continual succession of new surfaces which are to be depressed, and which 

 may be supposed to react on the ball, so as to produce the same effect as a 

 more intense pressure would have done, if it had continued stationary ; 

 and the mutual action of the water and the ball may be compared to the 

 impulse of an oblique stream, moving with the velocity of the ball, which 

 would impel it much more powerfully than the simple hydrostatic pressure 

 at a much greater depth. It happens in this case, as in many others, that 

 the effects which appear to be the most familiar to us, do not by any means 

 admit the clearest and simplest explanation. 



LECT. XXV. ADDITIONAL AUTHORITIES. 



L'Hopital on the Solid of least Resistance, Hist, et Mem. de Paris, 1699, p. 107, 

 H. 95. Craig on do. Ph. Tr. 1701, p. 746. Varignon on Motions in a resisting 

 Medium, Hist, et Mem. 1707, p. 382, H. 139; 1708, pp.212, 250, 302, 419, H. 

 123 ; 1709, 1710, 1711, p. 248, H. 87. Desaguliers on the Resistance of the Air, 

 from Exp. in St. Paul's Cathedral, Ph. Tr. 1719, No. 362. Pitot on the Oblique 

 Impulse of Fluids, Hist, et Mem. 1727, p. 49, H. 137. D. Bernoulli on Pres- 

 sure and Resistance, Com. Petr. iii. 214, iv. 136, v. 106, viii. 99, 113. Euler on 

 Friction and Resistance, Nov. Com. Petr. vi. 338, viii. 197. Bouguer on the 

 Solid of least Resistance, Hist. etMem. 1733, p. 85, H. 86 ; 1767, p. 504, H. 110. 

 On Impulse of Fluids, ibid. 1746, p. 237, H. 289. Manoeuvre des Vaisseaux, 4to, 

 1757. Krafft on the Impulse of a Vein of Water, Com. Petr. viii. 253 ; xi. 233. 

 D'Alembert, Essai sur la Resistance des Fluides, 4to, 1752. Silvabelle on the 

 Solid of least Resistance, Mem. des Savans Etrangers, iii. 639. Borda on the Re- 

 sistance of Fluids, Hist, et Mem. de Paris, 1763, p. 358, H, 118 ; 1767, p. 495, H. 

 145 ; 1769, p. 247. Lambert, Hist, et Mem. de Berlin, 1765, p. 102. Don Jorge 

 Juan, Examen Maritime, 2 vols. 4to, Madrid, 1771. Nouvelles Experiences sur la 

 Resistance des Fluides, par MM. D'Alembert, De Condorcet, et Bossut, 1777. 

 Bossut's Experiments, Hist, et Mem. 1778, p. 353, H. 38. Mann's Experiments 

 on the Resistance in shallow Canals, &c. Ph. Tr. 1779, pp. 555, 629. Euler on 

 the Impulse of a Vein of Fluid, in his Comment on Robins, 1783. Lagrange on do. 

 Mem. de Turin, 1784-5. Michelotti on do. Melanges de Turin, 1788, App. 121. 

 Legendre's Example of the Solid of least Resistance, Hist. etMem. 1786, p. 21, 

 App. 121. Lorgna,Mem. della Soc. Ital. 4to, 418. Vince on the Resistance of Fluids, 

 Ph. Tr. 1795, p. 24; 1798, p. 1. Gerstner's Theory of the Impulse of Water, 

 Abhandlungen derBomischen Gesellschaft, 1795. Experiments of the Society for the 

 Advancement of Naval Architecture, 4to, Lond. Charnock's Hist, of Marine Ar- 

 chitecture, 3 vols. 4to, 1800. Morosi on the Impulse of a Vein of Fluid, Mem. 

 dell' Institute Lombardo-Veneto, 1812, pp. 119, 305. Brunacci, Mem. della Soc. 

 Ital. 1816-17. Macneill's Canal Navigation, 4to, 1833. Beaufoy's Nautical and 

 Hydraulic Experiments, 4to, 1834. 



