This Table was computed by methods different from 
es these hitherto described, and ‘is iently correct to 
serve as a standard with which the results of the other 
imme ay Be compared. 
; The following Table contains the c rison of the 
son actual ial randoms, from trials made by Antoni 
tua! on the s of the Po, in June 1764, the barometer 
‘standing at 29 inches. 
A ae 3 
> ~ 
ae oe Hi 
33 Elevation. Yards! Yards.| 
b* 
_carabine, bullets axe 901/1990 
pa 2th ofanoz. {i , ori ata - oa 
7°.15 | 948) 78 
[Musket, the bullet  }, 179614 15° |1805)15690 
weighing 1 oz. 24°.20 |1335/2358 
. 45° (1181/3138 
aes 15° |1433/17897) 
ree } 1855 } 220 1753126734 
ayy yor 45° |1629/35794 
{watt | ret md 1770 {is [1699|16307| 
pi Balls weighing 
Ar uceaual 3 l2068| 4 15°" | |1630/29268) 
4 84 oz. balls. 
In order to determine experimentally the curve de- 
of scribed by projectiles, Antoni recommends the follow- 
the ing method. Choose a piece of ground on which the 
wescri- guns may be. placed at the different heights, A, C; D, E, 
pe and fire some rounds from A, the position and char 
of the gun remaining always the same. Having mark- 
2 ed the first graze of the shot at I, fire from C, D, F, 
‘XVI. with the same elevation, direction, and charge, and 
mark the aye at L, B, and Q. The perpendiculars 
IH, LK, BM, and QF, will be the abscisse of the curve 
ribed by the shot and horizontal lines; AH, CK, 
DM, and EF, will be the corresponding ordinates, 
from which the curve may be deduced, or traced me- 
y. 
; e same result may be obtained by firing the 
from different points of a horizontal Giienngainad the 
face of a mountain. 
. 
CHAP. Vi. 
Mr Robins’ Practical Maxims relative to the Effects and 
- Management of Artillery, the Flight) Shot and 
, Mazim I. 
._ In sny piece of artillery whatever, the greater quan- 
ity of powder it is charged with, the ter will be 
ae scheiay of the bullet. Pie 
. Maxim Il. 
"If two pieces of the same bore, but of different lengths, 
are fired with the same charge of powder, the longer 
will impel the bullet with a greater celerity than the 
Mazim TI. 
If two. pieces of artillery, different in weight, and 
GUNNERY. 
ai The greatest 
583 
formed of different metals, have their 
ual bores and equal ; then, with hke char, 
of powder and like bullets, will each of them dis- 
charge their shot with nearly the same celerity. 
Maxim IV. 
The r of pieces at a given elevation, are no 
measures of the velocity of the shot ; for the same piece 
fired successively, at an invariable elevation with the 
powder, bullet, and every other circumstance as nearly 
the same as possible, willrange to very differentdistances. 
Mazin V. 
The greatest part of that uncertainty in the ran 
of pieces, which is described in the preceding seated, 
can only arise from the resistance of the air. 
Maxim VI. 
The resistance of the air acts upon projectiles in a 
twofold manner ; for it opposes their motion, and by 
that means continually diminishes their celerity ; and 
it, besides, perpetually diverts them from the regular 
course they would otherwise follow ; whence arises 
those deviations and inflections mentioned in Maxim XI. 
Maxim VII. 
That action of the air by which it retards the motion 
of peaeriiee, is in mi instarices an immense force ; 
and hence the motion of these resisted bodies. is totally 
different from what has been generally supposed. 
Mazim VII. 
This retarding force of the air acts with different de- 
grees of violence, according as the projectile _moves 
with a greater or lesser velocity ; and the resistances 
observe this law: that to a velocity which is double 
another, the resistance (within certain limits) is four- 
fold, and to a treble velocity ninefold ; and so on. 
Maxim IX. 
But this proportion between the resistances to two 
different velocities does not hold, if one of the velocities 
be less than that of 1200 in a second, and the other 
greater. For in that case the resistance to the gene 
velocity is near three times as much as it would come 
out by a comparison with the smaller, according to the 
law explained in the last maxim. 
Maszim X. 
To the extraordi power exerted by the resist- 
ance of the air, it is owing that when two pieces of dif- 
ferent bores are discharged at the same elevation, the 
piece of the larger bore usually ranges farthest, provi- 
ded they are both fired with fit bullets, and the euss 
tomary allotment of powder. 
Maxim XI. 
of mili jectiles will, at the 
time of their discharge, ison piirlieg motion round 
their axis, by rubbing against the inside of their om 
tive pieces ; and this whirling motion will cause 
to strike the air very diferenty trom what they would 
do, had they no other but ap ive motion. By 
this means it will happen that the resistance of the air 
will not always be directly opposed to their flight ; but 
will frequently act in a line oblique to their course, 
and will force them to deviate from the 
tract they would otherwise describe. And this is the 
true cause of the irregularities described in Maxim IV. 
linders of Prnetiea! 
Maxime. 
Robins’ 
practical 
inaxims, 
