CORRECTIONS FOR QUICK TARGETS. 
3 
We see, therefore, that for objectives, moving at the same rate, and 
in the same general direction, the correction k is constant, for all posi¬ 
tions along a line through P, parallel to G A. Thus, if we draw G Q 
parallel to F F\ and Q P Q' parallel to G A, then whether the ship be 
at Qj P or Q!, the correction k will be the same, so long as the velocity 
and the direction of motion remain unaltered. 
By making use of this property we can evaluate the range correction 
for any point of a channel, by a simple graphic method. 
To make this clear, let us consider the case of the 10-inch B.L. gun, 
with a time of firing of three seconds and an objective of 20 knots, 
(v = 10). 
Let G be the position of the gnn and let G L be drawn parallel, and Vide Fig. 
GM perpendicular to, the general direction of the channel. Divide 
Fig- 2. 
Be 
p 
/ 
a 
P 
ii 
- :p. 
e 
e l 
. Pi 
-A 
a 
A 1 
_ pi 
- p* 
c 
c l 
Pi 
-A 
l 
ti 
pi 
-p 
a 
a 1 
.. 7} f 
A . 
B . 
500 WOO 1500 2000 2500 3000 3500 4000 4S0O 5000 YDS 
G M 
G L and G M into scales of equal, parts, to read seconds and fractions 
