CXCIV. GAUGING OF FLOW OF STREAMS AND ARTESIAN BORES. 
ing of the water level and the reading when fixed at crest 
level, gave the head. 
A section of the channel was taken at the hook gauge, 
and the discharge as computed from the observed head 
applied to it, to see whether there was any appreciable 
velocity of approach, if there was, which happens very 
rarely, the equivalent head was computed and inserted in 
the formula used given below, but as arule this equivalent 
head was vastly less than could be measured with the hook 
gauge, SO was neglected. 
The author considered that the formula given by Hamilton 
Smith, Jnr., was much more suitable for the small notch 
that he was using than Francis’ formula, as the notch was 
only two feet long and heads only about 5 inches at most. 
The formula used is 
Q=c2 /2gb(H + th)? 
Where Q = Cusecs. 
g = acceleration due to gravity. 
b = length of crest. 
H = head as measured by the hook gauge. 
h = head due to velocity of approach. 
A curve was drawn by plotting the following value of ¢ 
and corresponding effective heads : 
Effective head in feet. Coefficient c. 
“af °646 
i 5) °634 
Fe °626 
P25 "621 
1D °616 
4 "609 
3 "605 
6 °601 
7 °598 
°8 °595 
9 "592 
1°0 °590 
