The argument as to the vulnerability of shielded guns is not at present
strong. Sir George says (ib. p. 94), "If the high angle fire ... is ever
to find a favourable opportunity, it will surely be against a cupola,
the site of which can generally be determined with accuracy." On the
other hand he says (p. 90), "During the long and costly experiments
carried on at Bucharest in 1885-1886, 164 rounds were fired from the
Krupp 21 cm. mortar at targets of about 40 sq. metres area" (about 430
sq. ft.) "without obtaining a single hit. The range was 2700 yds.; the
targets were towers built upon a level plain; the shooting conditions
were ideal, and the fall of each shell was telephoned back to the firing
point; but it must have been evident to the least instructed observer
that to attempt to group 6 or 8 shells on an invisible area 2 metres
square would have been absolutely futile." These facts are adduced to
prove that it is not necessary to give great thickness to concrete
casemates, to resist successive bursts of shells in the same place; but
surely they are equally applicable to cupolas. Again (p. 252), "The
experience gained at Port Arthur was not altogether encouraging as
regards the use of high angle fire. The Russian vessels in the harbour
were sunk by opening their sea-valves.... Fire was subsequently directed
upon them from 11 in. howitzers at ranges up to about 7500 yds. This was
deliberate practice from siege batteries at stationary targets; but the
effect was distinctly disappointing." The cupolas therefore can hardly
be considered ideal targets: and the probability is that they would hold
their own against both direct and indirect fire for a long time. There
are other and stronger arguments against the general use of them, all of
which are clearly set forth by Sir George Clarke.
The worst objections to the cupola are the military disadvantages of
isolation and immobility, and the multiplication of mechanical
arrangements. For a successful round from a disappearing cupola, the
elevating and traversing arrangements, the elevating and loading gear of
the gun, and the telephone communication, must all be in good order. At
night the successful co-operation of the searchlight is also in many
cases necessary.
The teaching of history is all against immobile mechanical defences.
Initiative, surprise, unforeseen offensive action, keeping the besieger
in ignorance of the dispositions of the garrison, and of what progress
he is making: all these, with their influence on the morale of both
sides, tend towards successful defences and do not point towards the use
of armour.
It may further be said that the use of armour as a general rule is
unnecessary, because a concealed battery is a protected one; and with
the long ranges now usual for heavy guns and howitzers, there is not
generally much difficulty about concealment.
In the opinion, however, of the present writer an exception must be made
for guns intended to flank the line of defence, which would generally
need bomb-proof over-head cover. Further, when we leave theory and come
to the consideration of actual problems of defence, it will often be
found that it is necessary to place guns in certain positions where good
concealment cannot be got. In such cases some form of protection must be
given if the guns are to engage the concealed batteries of the attack.