436 MR. RENNIE ON THE FRICTION AND RESISTANCE OF FLUIDS. 
Let A = area of orifice in square feet. 
d = diameter of orifice if circular. 
H = altitude of the fluid in feet. 
T = time. 
g = gravity in one second. 
Q = quantity of water in cubic feet. 
According to Bossut’s experiments Q = 0.6 1 938 A T ^ 2 g H. 
And as 2 g is a constant quantity, and is equal to 7.77125, we have Q = 4.818 ATt/H for orifices 
of any form, substituting d if circular, or Q = 3.7842 d 2 T V H. 
From the second of these equations we obtain 
, Q T Q 1 II Q 
4.818 T^H “4.818 A a " d H “ (4.8J8 AT)*’ 
For additional tubes the equation will stand thus : Q = 0.81ATV2gH; but since 2 g is constant, 
and is 7.77125, we have Q = 4.9438 tZ^T V H, from which we deduce 
d = / Q T = 
V 4.9438 T V FI 4.94 
Q 
438 d l a/H 
H = 
Q 
(4.9438 cf~T) * 
Table VIII. 
Experiments on the Friction or Quantity of Water discharged by Leaden Pipes 
of different diameters and lengths, from a vessel kept constantly full, and at 
different heights. 
Pipes 15 feet long each, straight. 
Constant height 
of the surface of 
the water above 
the centre of the 
pipe. 
Time in discharging one cubic foot. 
Remarks. 
1 inch. 
% in. 
1 in. 
No leaden pipes 
to be had 5 bore. 
feet. 
seconds. 
seconds. 
seconds. 
4 
28 
54 
143 
The time in discharging one cubic foot 
3 
33 
63 
164 
is nearly double the time occupied by 
2 
41$ 
79 
208 
glass tubes of equal lengths and areas. 
1 
61$ 
117 
312 
