THE ROYAL ARTILLERY INSTITUTION. 
121 
Table I. 
Abstract of the Results of Experiments to ascertain the Initial Velocity 
of Service Projectiles fired from Service Guns with Service Charges. 
Nature 
of Ordnance. 
1 
Charge. 
Projectile. 
o • 
3 
& 
d 
£ 
Weight. 
Nature of Powder. 
Nature. 
1 
i? 
§ 
s 
Velocity 
30 yds 
Measure 
Precis 
'3 ° 
10-in. gun, 87 cwt. 
10 
lbs. oz 
12 0 
L.G.W. A., 26/11/60 
L. G. Hall and Sons, 
Hoi. shot 
lbs. oz. 
88 5 
9-838 
1270-4 
0-490 
1292-3 
Do. do. 
5 
8 0 
Mar. shell 
117 0 
9-838 
930-1 
0-175 
940*6 
68-pr., 95 cwt. - 
12 
16 0 
22/11/60. 
L. G. W. A., 26/11/60 
Shot 
66 4 
7-915 
1553-1 
0-703 
1579-0 
Do. do. 
7 
16 0 
L. G. Hall and Sons, 
Nav. shell 
51 8 
7-913 
1769-4 
0 237 
1809-9 
Do. do. 
9 
16 0 
22/11/60. 
Do. do. 
Com. shell 
49 14 
7*857 
1750-3 
0-348 
1790-7 
Do. do. 
5 
10 0 
L. G. Hall and Sons, 
Mar. shell 
60 0 
7*848 
1287-6 
0*131 
1308-5 
8-in gun, 65 cwt. 
5 
10 0 
22/11/60. 
Do. do. 
Hoi. shot 
46 0 
7-84 
1455-0 
0-504 
1487-9 
Do. do. 
5 
10 0 
Do. do. 
Com. shell 
49 14 
7-856 
1434*6 
0 573 
1464-4 
Do. do. 
5 
10 0 
Do. do. 
Nav. shell 
51 8 
7-92 
1475*8 
0-306 
1506-4 
32-pr., 58 cwt. - 
10 
10 0 
L.G.W. A., 26/11/60 
Shot 
31 6 
6-174 
1653-7 
0-425 
1690-0 
Do. do. 
11 
8 0 
Do. do. 
Do. - 
31 6 
6-176 
1584‘.7 
0-610 
1618*7 
Do. do. 
11 
6 0 
Do. do. 
Do. - 
31 6 
6*175 
1418-8 
0-504 
1447-5 
24-pr., 50 cwt. - 
11 
8 0 
Do. do. 
Do. - 
23 8 
5'602 
1679-5 
0-323 
1720-5 
18-pr., 3S cwt. - 
12 
6 0 
Do. do. 
Do. - 
17 11 
5-093 
1646-8 
0-148 
1690-6 
12-pr., 18 cwt. - 
10 
4 0 
L. G. - - - 
Do. • 
12 10k 
4‘52 
1718-6 
0*384 
1769*8 
9-pr., 13 cwt. - 
10 
2 8 
Do. - - 
Do. - 
9 5i 
4-10 
1563-9 
0-406 
1613-7 
6-pr., 6 cwt. - 
10 
1 8 
Do. - - 
Do. - 
6 3| 
3-58 
1435-3 
0-418 
1484-5 
12-pr. howr. 6| 
10 
1 4 
Do. - - 
Com. shell 
8 12 
4-454 
1124-2 
0-270 
1163*4 
cwt. 
24-pr. do., 12 
10 
2 8 
Do. - - 
Do. - 
16 Hi 
5-595 
1218-0 
0-368 
1252*7 
cwt. 
Wall piece 
8 
drs. 
8 
E. R. - - - 
Ball 
0 5| 
0*935 
1134*8 
_ 
1167*6 
Enfleid rifle 
3 
2’5 
Do. - - - 
M. ball - 
530 grs. 
0-577 
1188*7 
— 
1272*8 
6-pr. Armstrong - 
15 
lbs.oz. 
0 12 
A. 4, W. A., 5/9/60 
Seg. shell 
6 0 
2-585 
937-5 
_ 
946-4 
12-pr. do. 
10 
1 8 
A. 4, W. A. - - 
Do. - 
11 9 
3-084 
1180-9 
1-000 
1190*2 
The results with the 6-pounder Armstrong require confirmation. 
It will be observed that the values of the “ Measure of Precision ” 
for each of the series of which the result is here given is placed in the 
above table in a separate column. The value of this constant denotes 
the comparative regularity of the initial velocity. 
As might perhaps be expected, from the absence of windage, the 
12-pounder Armstrong has shown the greatest regularity, and I have 
therefore assumed the measure of precision for this gun as unity. 
An inspection of the values of the “ Measure of Precision ” will show 
how great is the amount of irregularity wdiich exists in the initial 
velocities of some of the projectiles tired from smooth bored guns. 
To illustrate the application of these constants, we may compare 
their values for the 12 -pounder howitzer and the 12 -pounder 
Armstrong, the velocities of the projectiles fired from these guns being 
nearly the same, but by the table it appears that the measure of 
precision in the former case is only about one-fourth of that in the 
latter case, or in other words the mean error in initial velocity alone is 
nearly four times as great. The great irregularity in the initial velocity 
of the Martin shells is also very conspicuous. 
15. The relation between initial velocity, weight of charge, weight 
of projectile, and length of bore is given (see Didion, “ Traite de 
Balistique,”) by the following equation :— 
v = 7 
C-’-C' 2 
■ 
( 7 ) 
when Y = initial velocity, //, = weight of charge, m — weight of shot, 
bottom, &c., M = quantity of powder required to fill the bore, C = 
