LAND AND .WATER 
August 14, 1915. 
X Now if a'6-incli shot grazes the point X and 
falls into the water, it falls at the point B beyond 
'the ship But the angle at which it is falling is 
60 steep that the difference in range between the 
point A and the point B is only 40 yards. To 
hit, then, with a 6-inch gun the range must be 
known within 40 yards. This interval is called 
the " Danger Space." 
The 9.2 will fall at a more gradual angle, and 
the shot grazing on X will fall at C, which is 20 
yards beyond B; and a 12-inch shell, falling still 
more gra-duallv, will fall at D, which is 100 yards 
from A; and similarly the 13.5 at E, which is 150 
yards beyond it. Hence, at any given range, far 
more accurate knowledge of range is necessary tor 
hitting with a 6-inch gun than with a 9.2, with a 
9.2 than with a 12-inch, and with a 12-inch than 
with a 13.5. 
But we have seen from Sketch 1 that, in pro- 
portion as the range gets long, so does the range 
accuracy of the gun decrease, and that this loss 
of accuracy is greater in small guns than iu 
bigger. To hit with it at all a more perfect fire 
conlrol is necessary, and for an}' given number of 
rounds a much smaller proportion of hits will be 
made. The advantage of the big gun over the 
small, merely as a hitting weapon, is twofold. It 
does not require such accuracy in setting the 
sight, and more shots fired within these limits will 
hit. 
FIRE CONTROL. 
If ships only engaged when they were 
Stat ion?. ry the range would not change, and it 
could be found by observation without range- 
finders. And even with range-finders it can 
never be found at great distances without observa- 
tion. But ships do not stand still, and when they 
move the distance between them alters from 
second to second. If these movements can be (1) 
ascertained, (2) integrated, and (3) the results 
impressed upon the sight, change of range would 
be eliminated, and we should have come back to 
the conditions in which ships were stationary. 
Fire control is successful in so far as it succeeds in 
doing these three things. The first two sketches 
places tfie target in one of the halves of thfe 
bracket. This half is bisected by the fourth shot, 
placing the target in a quarter. If an eijghth of 
the bracket is less than the danger space, then 
the fifth shot must hit. 
A- 
/ 
7 5 -r 4- 
In Sketch 5 the ships keep parallel courses 
for two minutes. The range does not change. 
The line in the graph (6) is horizontal. It is as if 
both were stationary. When the ships turn the 
range increases, and the graph rises. But the 
graph is not a straight line but a curve. This 
shows that the rate also is changing. Each 
"Mwu&s 
show the process by which hits are secured, when 
the conditions are not complicated by changes in 
the range, that is, if these complications have been 
eliminated by fire control. The second two illus- 
trate what these complications are. The ships turn 
away from each other and then turn towards each 
other. The rate graph shows the effect of these 
movements on the range and the rate af which 
it is changing from moment to moment. 
The processes shown in Sketches 3 and 4 is 
called " bracketing." Two shots are fired at a dif- 
ference of, say, 800 yards. Observation shows the 
«fe^- 1^ be too short, the second to be too far. 
The difference is bisected b^ tteTffiHl shot. TtH^;,^- 
SuptUmcnt to l,i.vD akd W«ter. August 14, mt 24* 
movement of the two ships, whether they keep 
steady courses or turn, alters the range and the 
rate. As projectiles take an interval of time to 
travel from the gun to the target, the range must 
be forecasted. B, then, cannot engage A, unless 
he knows where A is going to be. He cannot know 
this until A has settled on a steady course. While 
A is turning, then, he is safe from gun-fire except 
by a chance shot. B cannot engage while he is 
himself turning unless he can integrate his own 
movements with As. 
It is this l?,tter difficulty which largely ex- 
plains the duration of modern actions. Kt the 
mean range of each engagement, with ships stanch- 
ing still, Sydney could have sunk Emden in ten 
minutes; Infle.rible and Invincible could have 
sunk ScJianihorst and Gnelsenau in fifteen. But 
it was ninety minutes before Emden was driven 
on the- rocks, 180 before Scharnhorst sank, and 300 
before Gneisenau went under. 
ACTIOiN OFF HELIGOLAND. 
The plan of this action is compiled from the 
dispatches of the various commanders; but. no 
sufficient detail is given in these reports to enable 
accurate plans to be made. The features of this 
fight which are tactically interesting are 
numerous. The battle-cruisers, for instance, had 
to wait for some hours before the moment came 
for their intervention, and while at the rendez- 
vous they were repeatedly attacked by submarines. 
From the Vice-Admiral's dispatch, it would 
ftppear that this attaek-wasfi^sfcrarted -partly *by; 
