GUNNERY. 
ein proportion to its quantity 
with that of the larger, fas dk velocity of the bullet, when 
impelled by the explofion of the fmaller charge, will be to 
the velocity of a bullet fapaied b ‘ie charge in the 
ap ea eo of the quantities of t ae tive charges, 
ubduplicate ratio o 
tlre sce: Seceeiatcaled by twe oy eat -weight, being 
known to be tat of 1670 feet in 1”, the velocity communi- 
one penny-weight would be that of 482 feet in 
1" nearly ; but by repeated trials, differing little from each 
ec it has been found, that the real velocity acquired by 
the ball in this cafe, from the explotion of one Pe ae 
rather lefs than that of 400 feet in 1”, Whence it is 
iain, that the elafticity as one penny-weight of powder, 
when fired, is lefs in proportion to its quantity than that of 
twelve penny-weight, as it ought to. be by the theory. 
So if three penny-weight of spew der be een in the fame 
manner with the one penny-weight laft-mentioned, the real 
velocity the ball will acguire Pen the aE st will be from 
740 to 720 feet in 1". Whereas, Big CAPT the elafticity of 
three penny -vsight, when fired, to be in fimilar circum- 
fa es that of ee i BE the ve- 
locity acquired se oe ball fhould be 825 feet in 1", 
At is farther to be obferved, that the theory haebe 
OW! fes that in the firing of 
of its fubftance is ban vected: by the 
mation into a. ont elafti i 
ticity of which in proportion to its heat and denfi ity, Is the 
Fane with that of the common air in the like circumitances : 
her fuppofes, that all the force exerted by Peta 
in its moft violent operations, is no more than the aétion of 
te gelaicity of the fluid thus generated ; and thefe Peiost 
ne the velocities of bullets impelled 
: ree this theory s the inconclufivenef of what 
fome authors have advanced ee e 
articular 
vol. viii. 
feet ; fo shat ithe committee feem well warranted in their 
opi inion eae is to reconcile this with the fore- 
going eae, 
in the account of his b 
in caltbiary charges, the Westies of bullets bea ‘erin 
the experiments hitherto made are really fuch as ft 
aia 
in 
can snd Set the velocities py itil exceed the ieee 
computation. See Phil. Tranf. N° 465. or Martya’s 
& 
P c. 
If a pallet be’ laid ‘at a confiderable diftance from fe 
charge, the principles before laid down cannot then b on 
pled ts determine the velocity | of the ball ; they being only 
or gerald i For by what is fhewn under the ia 
Gunrowper, when the furface of fired powder is not con- 
HB by aheavy body, which it is obliged to impel before 
t, the flame dilates Bos with a velocity, much beyc 
pee it can at any time communicate toa Pallet by its cons 
tinued ae age the powder having acquired a 
ce Soa of eos of sxporlions. the fief motion of 
the ball wi be produced by the continual pei. 
the powder, but by the Se of the flame 
whence it follows, that the velocity of a bullet, laid at a 
confiderable diftance before the charge, ought to be greater 
than what would be communicated to it by the preflure of 
the powder aéting as before mentioned in this a And 
this deduétion from theory is confirmed from experiences 
by which it was found that a’ ball laid in a barrel, at the dif 
tance of 114 inches from the breech, and impelled by twelve 
ee AS of powder, acquired in its difcharge a velocity 
forms for ars and cannon; 0: t 1400 feet in 1"; whereas if it had been raéted on by 
i; all their laboured ‘peniaoe on | this head are = eomennty the ohne of the flame only, it would not have aye eda ve- 
founded on SES ns of fired locity of 1200 feet in 1. "The fame was found to h old true in 
pomdat Lib. c all other great diftances 
But it mut vs, is Peer that Eboneter probable this 
nd h 
on whic 
theory may be from the experimen re 
it is founded, there full remains a diffeulty ee feems not 
pon gave it as their ee: that the change | of 
the ae in ee chamber wi 
tance to. which the bullet is cheno 
a change of the dif- 
(and alfo in leffer, ae not in the 
And from 
in praé Etice, — 
fame degree) and i in val ied “2 = wder 
fortifi 
ex Ss 
ep by the 1 
be 
the progre 
may hence be iuppofed to be: er ae the expan 
saei+? ‘ighbouring parts. And it und that the 
ey 
Me 
