in which A equals the area of blade in square feet, V and v velocities
of current and wheel periphery respectively, in feet per second. Thus,
for example, a wheel 10 feet in diameter with blades 6 feet long and 1
foot in width, running in a stream of 5 feet per second--assuming the
wheel to be giving as much power as will reduce its velocity to one half
that of the stream--the figures will be

6' × 5' 2
------- × 2.5 = 0.468
400

[TEX: \frac{6' \times 5'}{400} \times 2.5^2 = 0.468]

horse power of the wheel.

The total power of the stream due to the area of the blade equals the

Square of the velocity of the stream
------------------------------------ ×
Twice gravity (64.33)

volume of water in cubic feet per second × 62.5 (weight of 1 C') = the
value or gross effect in pounds falling 1 foot per second. This sum
divided by 550 = horse power. Thus, as per last example,

2
5
------ × 30 × 62.5
64.33
---------------------- = 1.32 the horse power of the current