pipe was required for the grade of 3 ft. per 1000 ft.
_Test No. 1_.--On March 10th, 1908, a quantity of bran was poured into
the upper end of the 10-in. pipe at _A_ (Fig. 2), and the time of its
appearance at the lower end of the 16-in. pipe at _E_ was noted. The
time was 3 hours and 50 min.
This gave:
Area of 10-in. pipe = 0.5454 sq. ft.
" " 16 " " = 1.3960 " "
Length " 10 " " = 13,200 ft.
" " 16 " " = 47,500 "
Time, = 13,800 sec.
Let _x_ = velocity of flow in 16-in. pipe, in feet per second, then 2.56
_x_ = velocity of flow in 10-in. pipe, in feet per second.
From which:
13,200 47,500
------- + ------- = 13,800
2.56_x_ _x_
_x_ = 3.805
and 2.56_x_ = 9.740
The discharge is:
For the 16-in. pipe, 1.396 x 3.805 = 5.31 cu. ft. per sec.;
and, for the 10-in. pipe, 0.5454 x 9.74 = 5.31 cu. ft. per sec.
The question arose as to whether or not the particles of bran in the
water traveled as fast as the water flowed. It was also desired to check
by observation the relative velocities in the two pipes, as above
deduced.
_Test No. 2_.--To determine these points, a second test was made, on
March 31st, 1908, twenty days after the first one.
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