HYDRAULICS. 209 



COULOMB has made experiments on this kind of re- 

 sistance, Mem. de TInstitut National, torn. in. 

 p. 247., Sec. He found the part of the resistance 

 proportional to the velocity to be 17 times greater 

 in oil than in water. 



It must be remarked, that DON Gr. JUAN makes the 

 resistance which ships meet with proportional nearly, 

 cocteris paribus, to their velocities simply. Examen 

 Maritime, torn. IT. 194, 195. 



299- If a stream strike obliquely on a plane, its 

 force is less than if it struck directly on the same 

 plane, in the ratio of the square of the sine of the 

 obliquity to the square of the radius. 



If the area struck be 2 , v the velocity of the fluid, 

 and i the inclination or the angle which the plane 

 makes with the direction of the stream, the force 



This conclusion does not agree with experience, ex- 

 cept when the angle i is greater than 60 degrees. 

 BOSSUT, Hyd. vol. i. 375. It appears, from ex- 

 periment, that the resistance to oblique planes con- 

 sists of two parts, one of which is proportional to the 

 square of the sine of 2, and the other to a certain 

 power (3.J) of the angle i itself. BOSSUT found, 

 that if a prow, in the form of a wedge, be drawn 

 through a fluid, and if the 'complement of the angle 

 which either face makes with the direction of the 



VOL. I. O stream 



