THE ROYAL ARTILLERY INSTITUTION. 
125 
Table IV. 
Abstract of the Results of Experiments to ascertain the Initial Velocity 
of 12 -pr. Armstrong Projectiles in Terms of the Weight of the 
Charge. 
Arm¬ 
strong 
12 -pr. 
No. of 
Rounds. 
Charge. 
Projectile. 
Velocity 
at 
30 yards. 
Initial 
Velocity. 
Remarks. 
Weight. 
Diam. 
lbs. oz. 
lbs. oz. 
ft. 
i 
r io 
1 4 
11 9 
3*084 
1055-3 
1063*1 
1 
i 
1 10 
1 6 
J 99 
3*085 
1092*4 
1100-7 
! 
No. 224 - 
; io 
1 8 
99 99 
3-084 
1180*9 
1190-2 
>■ 1 st series. 
10 
1 10 
99 99 
3-084 
1224-8 
1234'6 
L io 
1 12 
99 99 
3*084 
1262-0 
1272-2 
J 
r io 
0 14 
99 *5 
3*084 
803-8 
809-2 
■j 
! 
10 
1 0 
99 99 
3-084 
863-9 
870-0 
1 
10 
1 2 
3-084 
924-6 
931-1 
No. 1050 
< 
10 
1 4 
99 99 
3-084 
997-8 
1005*1 
Y 2 nd senes. 
10 
1 6 
99 99 
3-084 
1050*2 
1058-0 
1 
1 10 
1 8 
99 99 
3-084 
1106-4 
1114-8 
L io 
1 10 
99 99 
3-084 
1178-0 
1187*3 
J 
Table V. 
Table showing the Velocity of a 12-pr. Armstrong Projectile in 
relation to the Weight of the Charge. 
Weight 
Initial 
Weight 
Initial 
Weight 
Initial 
Remarks. 
of 
of 
Charge. 
Velocity. 
Charge. 
Velocity. 
Charge. 
Velocity. 
lb. oz. 
ft. 
lb. oz. 
ft. 
lb. oz. 
ft. 
0 14 
870 
1 3 
1,036 
1 8 
1,190 
The weight of the projectile 
for this table is 11 lb. 9 oz. 
0 15 
908 
1 4 
1,063 
1 9 
1,214 
1 0 
943 
1 5 
1,087 
1 10 
1,234 
1 1 
976 
1 6 
1,119 
1 11 
1,254 
1,272 
1 2 
1,007 
1 7 
1,155 
1 12 
Variation in the Initial Velocity of the Armstrong Projectiles in terms 
of the Weight of the Shot. 
22. From the considerations mentioned in the foregoing paragraph 
it would naturally be expected, that if the weight of the shot be varied 
instead of that of the charge, there would be a much smaller discrepancy 
between the computed and the observed velocities, as in this case the 
charge remaining the same, there will be no variation in the amount of 
air space in the powder chamber. 
23. The series XXIX. to XXXI. and Till, to TVII. were undertaken 
with a view to elucidate this point. A graphical representation of the 
observed and computed velocities is delineated in fig. 3, the computed 
velocities being obtained from— 
/ j. ^ HFA 
Y = 3358-9 /-—log-— 
/ v m + ~ r 
and a glance will show how closely in this case, the observed velocities 
accord with the hypothetical ones. 
