4, 
to the defence, and as their supply of ammunition should be practically unlimited, 
they must utilize this advantage by rapidity of fire, and this rapidity must be 
sought not only by employing hight guns but also by the use of fixed ammunition 
and short recoil mountings. 
The armament of a fortress may be classified as under— 
(1.) Protective armament—consisting of guns permamently mounted in the 
forts of the main line. These guns are thus always ready and can join in the 
defence at the very outset—they include the long range guns mentioned above— 
strongly protected and even some in armoured revolving towers ; quick-firing and 
other light or medium guns and howitzers for the immediate protection of the forts 
themselves, and for flanking purposes, mounted on disappearing mountings. 
(2.) Defensive armament consists of the ordnance which it is intended to place 
in position as soon as it has been decided to put the fortress in a state of defence, 
these guns, &c. would be distributed in the intervals between the forts, in batteries 
of the nature of siege batteries. 
(3.) Reserve armament.—This armament is intended to reinforce the face or posi- 
tion attacked and could only be placed in position when that is known; the batteries 
composing it would be told off to the main and second or retired lines respectively. 
(4.) Mobile armament consists of field and mountain batteries intended to 
accompany the mobile troops of the sectional or general reserve and to support 
their operations. 
Placed behind epaulments they would assist in the general defence of the various 
lines, and form a reinforcement to the regular armament of the fortress. 
Tt has been said above that the bulk of the armament would be placed in the 
intervals between the forts and that these interval lines should follow the 
topographical crest of a series of ridges. 
These batteries should be arranged andin three échelons, the first on the crest 
line should consist of medium and small calibre guns for direct fire, they should 
have a command of fire and view over the eround j in front, they are for direct fire 
and should be aimed by direct visual laying ; the second echelon should be placed 
a little behind the crest line or on high eround to the rear not commanded from 
the front, and should consist of medium and fairly large calibre guns with flat 
trajectory for direct fire; the third echelon should be on the reverse slope and 
should consist of medium and large calibre howitzers in concealed batteries for 
indirect fire by indirect laying. 
Defence of the advance line.—The protective armament placed in the first and 
second échelons of the intervals should endeavour by direct fire to silence the be- 
sieger’s guns charged with the duty of preparing for the assault on the advanced 
line, the careful organization and the superior means of observing fire at the 
disposal of the defence should ensure a superiority of fire. The long range guns 
in the forts would prevent the enemy from bombarding the advanced position 
from close quarters and would support the troops engaged in the defence of that 
position. The light mobile guns in the advanced “position would support the 
infantry in its defence and cover its retreat. 
Carefully arranged lines of obstacles would add to the efficiency of the artillery 
fire from the main line of defence by delaying the attacking columns. Wire en- 
tanglements, owing to the comparative immunity they enjoy from destruction by 
artillery fire, form the best kind of obstacle—they should have a depth of from 200 
to 300 yards—with intervals 400 to 600 yards wide at certain known points to 
allow the defenders to fall back thr ough them. 
Defence of main line.—Artillery combat—the main burden of the defence during 
this phase will fall on the third échelon of the defensive armament, i.e. those 
howitzers placed in concealed batteries on the reverse slopes of the ridge. From 
