398 
EXPERIMENTS on the VELOCITY of 
AIR zssuing out of a Vessel in different 
circumstances; with the Description of an 
instrument to measure the force of the Blast 
in Bellows, 8c. By Mr. BANKS, Lecturer 
in Natural Philosophy. Communicated. by 
Mr. DALTon. 
READ, MAY 30, 1800. 
Tue object of this enquiry may be announced 
in the following proposition. If an elastic fluid 
‘is generated in a given vessel, orany way contained 
in it, andat liberty to issue out of the said vessel 
through a given aperture, to determine the resist 
ance which the vessel meets with from its action, or 
the power which it has of communicating motion 
to the vessel, asin a sky rocket, Saddler’s steam~ 
engine, &c. 
Before we proceed to relate the experiments it may 
be proper to premise certain principles deduced 
from Theory. Ifa tube be filled with any kind 
of fluid, as air, water, mercury, &c., and placed in 
a vacuum, every fluid -will flow out with the same 
velocity. For though the pressure of a column of 
mercury of a given altitude, be much greater than 
