54 
THE CONCENTRATION OF FIRE FROM FORTS. 
Both in 2 and 3 there would be a directing gun for each group, with 
reference to which the deflection of the other guns would be given by 
their training pointers, but while in 2 it would be a permanent deflec¬ 
tion and only suitable for one range, in 3 the pointer could be adjusted 
for every range, or as often as is considered necessary. 
I would have the deflection. scale in 3 graduated in yards to corres¬ 
pond with the ranges for which deflection is given; and, as deflection 
will always be given in the same direction, the pointer should only be 
capable of sliding towards the directing gun of its group. 
It would be the duty of the gun layer, who knows approximately 
the range at which his gun is firing, to set the training pointer to that 
range on the deflection scale before giving the final training to his 
gun ; even if he should forget to attend to this, ranges do not alter so 
suddenly in action that any great error in direction is to be feared. 
A pointer of this description, if desired, could be locked in any 
position and used as a fixed pointer. 
It will be sufficient to graduate the deflection scales for ranges of 
1000, 2000, &c. yards, unless the guns are at a considerable interval. 
Suppose a gun is 30 feet from its directing gun and .the radius of its 
training arc is 15 feet, then the length of deflection scale required to 
make the two guns converge at 1000 yards works out to 1^ inch, and 
this would be the maximum needed for the gun in question. For a 
given radius the length of scale varies directly as, and in proportion to, 
the interval between guns, and under ordinary conditions it would not 
exceed 6 inches. 
A good method of giving traversing motion to the pointer appears 
to be that adopted in sights for B.L. guns for moving the deflection 
leaf. Diagram (<?.) 
Diagram (c.) 
a = Deflection scale. 
/3 = Training pointer. 
7 = Bracket for same with 
index. 
8 = Traversing screw. 
= Gfuide slots for bracket. 
In my opinion, if the fire of groups were concentrated on one portion 
of the objective it would be more effectual both actually and morally, 
and if any better method of doing it than the above can be devised, I 
shall be very glad to see it introduced. 
SnOEBTJRTNESS, 
October 1891. 
