203 OUTLINES Or NATURAL PHILOSOPHY. 



TO- 



See Du BUAT, ubi supra, 51., &c. At 42. p. 65. 

 the formula is reduced to English measure, as now 

 given. 



When II and S are very great, V = 



^ / 307 3\ 



R* I : 5 1 nearly. 



^-JV*S ^ 



The logarithms understood here are the hyperbo- 

 lic. 



The slope remaining the same, the velocities are as 



-. 



10' 



The velocities of two great rivers that have the same 

 declivity, are as the square roots of the radii of their 

 sections. 



If R is so small, that R^ ~ = 0, or R = JL, 



J.U J. UU 



the velocity will be nothing ; which is agreeable to 

 experience ; for in a cylindric tube R = \ the ra- 

 dius of the cylinder; the radius, therefore, equal 

 / 5 of an inch ; so that the tube is nearly capillary, 

 and will not admit the water to flow through it. 



The 



