When the velocity of the floating body is greater than that of 

 the wave, the effect of the wave is to diminish the resistance of the 

 fluid. 



The manner in which tlie wave increases the resistance opposed 

 to a fluid, is by increasing the immersion of the anterior part of the 

 solid, by raising the front and leaving the stern depressed in the 

 hollow behind the wave, so that the transverse section of resistance 

 has an increment of area in the ratio of the rise of the elevation. 



The manner in which the wave diminishes the resistance at velo- 

 cities not less than that of the wave, is by falling behind the stern^ 

 so as to raise a portion of the vessel equal to itself above the mean 

 level of the fluid, thus diminishing the anterior section presented to 

 the vessel. 



At all velocities greater than that of the wave, the displaced 

 fluid falls behind the prow, and forms a compound wave, on the 

 ridge of which the vessel is carried along with diminished anterior 

 immersion. 



These doctrines receive illustration from the navigation of shal- 

 low rivers and canals, and are applicable to the improvement of in- 

 land transport by water. 



Monday, Itfh April 1837. 

 Sir HENRY JARDINE in the Chair. 

 The following Donations were presented : 



Comptes Rendus Hebdomadaires des Seances de I'Academie des 



Sciences (1837, 1" Semestre), Nos. 12 and 13— Bi/ the 



Academy. 

 Bulletin de I'Academie Royale des Sciences et Belles Lettres de 



Bruxelles. Annies 1832, 1834, 1835, Nos. 4, 5, 6, 7 ; and 



1836, Nos. 8 and 12. 

 Essai Historique sur la Vie et la Doctrine d'Ammonius-Saccas, chef 



d'une des plus celebres Ecoles Philosophiques de I'Alexandrie 



Par L. J. Dehaut. 

 Memoire sur les Proprietes et I'Analyse de la Phloridzine. Par. L. 



de Koninck. 

 Annuaire de I'Obscrvatoire de Bruxelles pour I'an 1837, par le Di- 



recteur A. Quetclet. 



