e correspondingly high, and the big gun in the
fortress was pretty certain to overwhelm the majority of them at least.
It is evident that the circumference {~GREEK SMALL LETTER
ALPHA~}{~GREEK SMALL LETTER BETA~}{~GREEK SMALL LETTER GAMMA~} offers
far more chances of hiding than the circumference ABC, but a still more
powerful factor in favour of the new big howitzer is the practical one
that at very great ranges in our climate the chances of spotting a
particular place are extremely small. Secondly, because the explosives
used, even when they landed and during the short time that the howitzer
remained undiscovered and unheard, were not sufficiently powerful nor,
with the small howitzers then in existence, sufficiently large in
amount in each shell to destroy permanent fortification. Thirdly,
because the effect of the aim is always doubtful. You are firing at
something well above yourself, and you could not tell very exactly
where your howitzer shell had fallen.

[Illustration: Sketch 20.]

What has modified all this in the last few years is--

First, the successful bringing into the field of very large howitzers,
which, though they do lob their shells, lob them over a very great
distance. The Austrians have produced howitzers of from 11 to 12
inches in calibre, which, huge as they are, can be moved about in the
field and fired from any fairly steady ground; and the Germans have
probably produced (though I cannot find actual proof that they have
used them with effect) howitzers of more than 16 inches calibre, to be
moved, presumably, only upon rails. But 11-inch was quite enough to
change all the old conditions. It must be remembered that a gun varies
as the _cube_ of its calibre. A 12-inch piece is not twice as powerful
as a 6-inch. It is _eight times_ as powerful. The howitzer could now
fire from an immense distance. The circumference on which it worked
was very much larger; its opportunities for finding suitable steep
cover far greater. Its opportunities for moving, if it was endangered
by being spotted, were also far greater; and the chances of the gun in
the fortress knocking it out were enormously diminished.

Secondly, the high explosives of recent years, coupled with the vast
size of this new mobile howitzer shell, is capable, when the howitzer
shell strikes modern fortification, of doing grievous damage which,
repeated over several days, turns the fort into a mass of ruins.

Thirdly, the difficulty of accur