The question has of course long passed beyond the stage of theory.
Practically every European state uses iron or steel casemates and
cupolas. German, Danish, Italian and other types of forts so armed have
been shown. Recent French types have not been published, but it is known
that cupolas are employed; and Velichko, the Russian authority, long an
uncompromising opponent of armour, in the end changed his views. These
countries have had to proceed gradually, by improving existing
fortresses, and with such resources as could be spared from the needs of
the active armies. Among the smaller states Rumania and Belgium have
entered most freely into the new way. In England, which is less directly
interested, opinion has been led by Sir George Clarke, since the
publication in 1890 of his well-known book on fortification. Having
witnessed officially the experiments at Bucharest in 1885 with a St
Chamond turret and a Gruson cupola, he expressed himself very strongly
against the whole system. Besides pointing out very clearly the
theoretical objections to it, and the weak points of the constructions
under experiment, he added: "The cost of the French turret was about
L10,000 exclusive of its armament, and for this sum about six movable
overbank guns of greater power could be provided." In view of the weight
that belongs of right to his criticisms it is as well to point out that
while this remark is quite true, yet the six guns would require also six
gun detachments, with arrangements for supply, &c.; a consideration
which alters the working of this apparently elementary sum. The whole
object of protection is to enable a few men and guns successfully to
oppose a larger number.
At the time when Sir George Clarke's first edition came out, such
extravagances were before the public as Mougin's fort; "a mastless
turret ship," as he called it, "buried up to the deck-level in the
ground and manned by mechanics." Such ideas tended to throw discredit
on the more reasonable use of armour, but whether the system be right
or wrong, it exists now and has to be taken account of. Nowhere has it
been applied more boldly than in Rumania. The defences of Bucharest
(designed by Brialmont) consist of 18 main and 18 small forts, with
intermediate batteries. The main forts are some 4500 yds. apart, and
11,000 to 12,000 yds. from the centre of the place. The typical
armament of a main fort is six 6-in. guns in three cupolas (one for
indirect fire), two 8.4-in. howitzers in cupolas, one 4.7-in. howitzer
in a cupola, six small Q.F. guns in disappearing cupolas. The total
armament of the place (all protected) is eighty-six 6-in. guns,
seventy-four 8.4-in. howitzers, eighteen 4.7-in. howitzers, 127 small
calibre Q.F. guns in disappearing cupolas, 476 small calibre Q.F. guns
in casemates for flanking the ditches. The "Sereth Line" will be
described later.
_Different Forms of Protection: Casemate, Cupola, &c._--The broad
difference between casemates or shielded batteries and turrets and
cupolas is that the former are fixed while the latter revolve and in
some cases disappear. The casemate thus has the disadvantages that the
arc of fire of the gun, which has to fire through a fixed embrasure or
port-hole, is very limited, and that the muzzle of the gun and the
port-hole, the weak points of the system, are constantly exposed to the
fire of the enemy. The advantage of the casemate lies in its comparative
cheapness and the greater strength of a fixed structure. It is well
suited for barrier forts (fig. 53) and other analogous positions; and
the Italians amongst other nations have so employed it at such places as
the end of the Mont Cenis tunnel. Steel and iron casemates are also
useful as caponiers for ditch flanking (fig. 55).
[Illustration: From Leithner's _Bestandige Befestigung_, by permission.