On the Velocity of Aur. 404 
would be gradually diminishing, and of conse- 
quence the pressure would be constantly chang- 
ing, hence the open end of the tubeis as near 
the top of the vessel as is consistent with a free 
passage for the water, 
Experiments. 
The vessel 4 contained 15\b. 6 oz. of water, 
from which we find its capacity is 425.088 cubic 
inches. 
The area of the aperture a, through which 
the air is expelled is ,o046 inches, 3 
Exper. 1st. The altitude of T above the vessel 
is 30 inches. Time of expelling the 
air by several trials is 33 seconds. 
Exper. 2d. Thealtitude of Tis 6 feet. The 
time of filling by several trials is 21.3 
seconds, 
In the first experiment, 425.088, the solidity 
of the vessel, divided by ,0046, the area of the 
hole a, gives 92410.4 inches for the length of 
the stream of air driven out in 93 seconds; 
divide that length by 33, and we shall have 293.3 
feet, the velocity per second, communicated by 
30 inches of water, 
