[ ] 
VII. An Account of a Book intituled, New 
Principles of Gunnery, containing the De- 
termination of the Force of Gunpowder 5 
and an Inveftigation of the refilling Power 
of the Air to (wife and flow Motions 5 by 
B. K . F. R. S. as far as the fame relates to 
the Force of Gunpowder. 
Read April 14,. 
and 2 1 . 1 74.3. 
r | 'HI S Treatife contains Two Chap- 
j[ ters. The Fil'd treats of the Force 
of Gunpowder, and the Velocities communicated to 
Bullets by its Explolion : The Second confiders the 
Refiftance of the Air to Bullets and Shells moving 
with great Velocities 5 and endeavours to evince, that 
this Refiftance is much beyond what it is generally 
efteemed to be; and confcquently that the Trad 
deferibed by the Flight of thefe Projediles, is very 
different from what is ufually fuppofed by the modern 
Writers on this Subjed. 
The principal Points endeavoured to be eftablifhed 
in the Firft Chapter are thefe, “ That the Force of 
fired Gunpowder is no more than the Adion of a 
permanent elaftic Fluid, which is produced by the 
Explofion ; that this Fluid obferves the fame Laws 
with common Air in their Exertion of its Prelfure 
or Elafticity ; " and confequently, “ That the Ve- 
locities communicated to Bullets by the Explofion 
may be eafily computed from the common Rules, 
which are eftablifhed for the Determination of the 
Ait’s Elafticity. ” 
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