THE ROYAL ARTILLERY INSTITUTION. 
329 
10, Tables I and II speak for themselves, except in respect to the last 
four columns, which may require some little explanation. 
Column 12, headed “ Mean difference of range,” is the arithmetical mean 
of the quantities by which each individual shot differs, in point of range, from 
the mean of the whole. Its amount is therefore a measure of the irregularity 
of range of the gun. 
Column 13, headed “ Mean observed deflection,” is the mean of all the 
deviations from the line of fire, whether to right or left. 
Column 14, headed “ Mean reduced deflection,” is the mean of the devia¬ 
tions, referred, not to the line of fire, but to the mean direction of all the 
shots; thus eliminating derivation and other causes influencing them all 
alike; also wind, so far as it affects direction, but not as affecting range. It 
was originally intended to have reduced all the deflections to their value at 
the mean range, and this would have been necessary if they had all been 
referred to one line of fire; but each having been referred to its own line of 
fire, the comparison is fair; and the mean deviations are the same as if this 
somewhat laborious reduction had been made. 
Column 15, headed “ Area of rectangles,” is the area of that rectangle into 
which, by calculation of probabilities, one-half of the shot at each distance 
may be expected to fall.* The area is perhaps the most convenient datum 
for tabular comparison; but the length and width are given in Table VIII., 
p. 335. 
11. It will be observed, that as the several competitors were not limited 
in the weight of the projectile they might employ with a rifled cast-iron 
32-pr. gun, or in their charge, they adopted charges which bear very different 
proportions to the weight of the shot: the ranges obtained, therefore, under 
the same degrees of elevation, are not directly comparable. The charges, in 
order of relative amount, are as follows 
Table III. 
Name. 
Charge. 
C 
Shot weight. 
P 
C 
P 
Smooth bore 32-pr. 
lbs. oz. 
10 0 
lbs. 
31-4 
•312 
French system . 
5 
8 
Shell loaded. 
64-7 
•085 
Shunt rifle. 
5 
8 
56-3 
•098 
Britten . 
5 
0 
50-4 
•099 
Jeffery. 
5 
8 
47-9 
•115 
Lancaster . 
6 
0 
50-8 
•118 
Service B.L. 40-pr. 
5 
0 
40-5 
•123 
Lynall Thomas . 
7 
0 
66-6 
•124 
Haddan . 
7 
0 
54*5 
•128 
Scott . 
6 
2 
43-7 
•140 
To obtain a direct comparison of range, it was decided to fire the whole 
with equal relative charges of one-tenth the shot’s weight. The results are 
contained in the following Tables :— 
* See a Paper by Captain A, Noble, in the “ Occasional Papers” of tbe Royal Artillery Institution, 
Vol. I. p. 173. 
