128 
MINUTES OF PROCEEDINGS OF 
second case is due to the escape of gas by the grooves in the rifled 
gun. 
Table X. 
Abstract of Experiments to ascertain the comparative Velocities of the 
same Shell fired from rifled and smooth bored 3 2-prs. of 58 cwt. 
Nature 
of 
Gun. 
Projectile. 
Velocity 
at 
30 Yards. 
Initial 
Charge. 
Nature. 
Weight. 
Diameter. 
V elocity. 
Remarks. 
32-pr. rifled 
lbs. oz. 
5 8 
PL shell 
.lbs. oz. 
54 0 
6*350 
1215*7 
ft. 
1224*5 
99 99 
>j » 
54 0 
6*350 
1122*1 
1135*3 
Nibs of shell removed. 
32-pr.58 cwt 
” ” 
” ” 
54 0 
6-350 
1187*4 
1201*7 
Do. do. 
27. With the same rifled 32-pr. gun experiments were also made to 
ascertain the reduction in the initial velocity due to an elongation in the 
cartridge, and the results of these experiments are here tabulated. 
Table XL 
Abstract of Experiments made to ascertain the Initial Velocities of 
Projectiles fired from a 32-pr. rifled Shunt Gun , with Charges 
made up in Cartridges of various Lengths. 
Nature 
of 
Gun. 
No. of Rounds. J 
Cartridge. 
t Projectile. 
Velocity 
at 
30 Yards. 
Initial 
Velocity. 
Remarks. 
Charge^Length. 
Nature. 
Weight. 
Diameter. 
Rifled J 
32-pr. j 
l 
4 
3 
1 
1 
2 
lbs. oz. 
5 8 
12 ins. 
9 „ 
8 „ 
7-1 „ 
6 „ 
■ v llT 
lbs. oz. 
54 0 
6*350 
6*350 
6*350 
6*350 
6*350 
1054*6 
1076*8 
1102*2 
1114*5 
1187*9 
ft. 
1061*7 
1084 2 
1109*8 
1122*3 
1196*4 
— 
From the rapid decrease in the initial velocity shown in this table, 
the effect of the variation in air space in the 12-pr. Armstrong, to 
which I have already alluded, will be easily understood. 
28. The experience of the preceding practice, together with theo¬ 
retical considerations, having pointed to a probable decrease in velocity 
should the diameter of the projectiles be diminished or reduced to that 
of the bore, the experiments numbered LXIX. to LXXXI. were under¬ 
taken with the object of corroborating or disproving this view. 
From the abstract of this interesting series it will be seen that while 
the velocity of the projectiles under normal circumstances was 
1248*2 ft. per second, when their diameter was reduced to that of 
the bore, with the exception of a narrow band at the back end, it 
became only 1209*7 ft. per second ; and when the diameter was finally 
reduced throughout to that of the bore, it was reduced to 1172*8 feet. 
In the rounds fired with the reduced diameters, the projectiles in all 
cases appeared to be perfectly steady in flight. 
