new species of Locomotive Vessel, 449 



munication between the distant races of men ? Let us not, 

 however, consider these advantages as yet within our grasp : 

 it will be quite sufficient if the demonstration here offered of 

 this new principle have no lurking fallacy within it : to all 

 appearance the result seems as undeniable as that of any 

 other mathematical demonstration when applied to mechanical 

 power. 



It has been ascertained, by the careful and s<itisfactory 

 experiments of the French Academy, that the resistance to 

 oblique surfaces moving through water by no means varies in 

 the duplicate ratio of the sines of the angles of incidence, as 

 has been theoretically supposed. 



Fifteen boxes were made, two feet wide, two feet deep, and 

 four feet long : one of them was a parallelopiped of these di- 

 mensions; the others had prows of a wedge form, the angle 

 varying by 12° from 12° to 180°, so that the angle of inci- 

 dence increased by 6° from one to another. When the prow 

 was at an angle of 12°, and the angle of incidence 6°, as shown 

 at Plate IV. fig. 3, the resistance was as 3-999 to 10*000 on the 

 base or front surface of the parallelopiped, say practically as 

 4 to 10. 



By the same authority, the resistance to one square foot, 

 French measure, moving with the velocity of 2*56 feet per 

 second, was very nearly 7*625 pounds French. The resist- 

 ances increased very correctly as the squares of the velocities; 

 and reducing these to English measures, a square foot moving 

 perpendicular to itself in river water, receives one pound re- 

 sistance when moving with a velocity of 1*01, say 1 foot, per 

 second. 



Let AB, fig. 1, be a plane moving perpendicular to itself in 

 water from A to H, and let the velocity be represented by the 

 line AH : the resistance to AB will be as AB x AH 2 . If the 

 plane AB move towards E, parallel to itself, with a velocity 

 A/z = AH, the resistance to its perpendicular section AH will 



AH 



be expressed by -rw. But experiment has proved that the 



2 2AH 



resistance to AB is - of that to its perpendicular AH, viz. ttw* 



If AB move to E with the velocity AE, the resistance will 



2AH 



be , . n x AE 2 ; and the power required to overcome this 

 5AB F 2 l AH 



resistance of AB towards H, as - . ^ x AE 2 . x AE is to 



5AB 



AB.xAH 2 . xAH. 



Let the plane AB be ten feet long by one broad, and let 

 the distance from A to H be one foot ; then if it be depressed, 

 Phil. Mag, S. 3. Vol. 37. No. 252. Dec, 1850. 2 G 



