NAVIGATION OF SHALLOW RIVERS. 



75 



less than those of the former curve, and a point of maximum when v = -g, and 

 of minimum when v = 2g. — (See Fig. 9.) 



The hne of resistance (AW?wM,R) corresponding to Eq. (3.), lies above the 



parabola, when - ^_^ -is greater than ms \^ sin 6\ becomes infinite when 



v^w and falls below the parabola, when the velocity becomes greater than that 

 of the wave, or when v -^ w. — (See Fig. 9.) 



Fig. 9. 



The lines of resistance derived from the experiments in Part III. are given 

 in Fig. 10 ; — velocities being measured on AY, and resistances being taken paral- 



