~ 236, . On the Measure of 
D made just to touch the side of the vessel... 
—The. orifice. was then opened, and the ~ 
water in the vessel was kept uniformly at 
the .same height. by’ a. stream falling 
gently on the plate E. The scale F having 
been raised by the reaction of the jet, 
weights were put into it till it was brought: 
exactly to the position in which it was before 
the orifice was opened, The diameter of the 
vessel was 7 inches, and the height BC ex- 
actly 3 feet. I tried orifices of various dia- 
meters from .85,to .7 of an inch. Their 
exact diameters were ascertained by a micro- 
meter, and the time carefully observed in . 
which 30 Ibs. of water were discharged through 
each orifice. 
When the orifice was made ina thin plate 
(3's of an inch in thickness), [ found the re- — 
action to be greater than Sir Isaac Newton’s 
first conclusion, in the ratio of 1.14 to 1. 
There was some variation in the results of the 
experiments. The greatest reaction, however, 
was as 1.16 to 1, and the least as 1.09 to 1, 
which fall far short, of Sir Isaac Newton’s last 
inference. The velocity of the water at the 
orifice (ascertained by observing the time in 
which 30 lbs. were discharged) was less than 
that which a body would acquire in falling 
freely from B to C, in the ratio of .6 to 1. 
