28 Hydraulics of the Mississippi River. 
parameter of the curve of parameters, and 5p o the ordinate, 
1 
= 1 
( =) peed | eed pot (bv)? 
The value of . Bs ges from the equations of subsurface veloct- 
ties, was 0° 
Referring es ‘the equation of the parabola before given, as 
adapted to the case in which the curve intersects the axis at @ — 
point of which the coérdinates are x=x,, y=0, viz: 
= x, 
7", 
rz, 
it will be seen that this value of = >is the coéfficient of y?, or 
2, ms 
— = me 
the negative vee ea cae by the nature of the case, — 
since x, is the maximum velocity in the vertical curve. Putting — 
then V for ie general value of the velocity in the subsurface — 
curve, and Vu, for the particular velocity at the depth d,, which — 
denotes the depth of the axis, the general equation of the sub- . 
surface velocities is 
=Va,— (b0)*d,2, 
where d,, denotes the distance of the point whose velocity 8 | 
- ere om the axis, expressed in decimals of the depth taken 3 — 
his curve ° was not so ph see 
2 obeeryed and compute velocities, scree 
mean diference is not a sixth of an inch. § 
: 
