both sides {81} are in the nature of a siege, and however
prolonged the siege, the advantage will be gained in the long run by
superiority of aggressive action in the air and over and under the
ground. In addition to the absence of opportunity for the grand
offensive there are two further points of difference between defensive
action in Position Warfare and the defence in a War of Manoeuvre. The
first of these is the inevitable absence of flanks to be assailed, as
the operations necessitate a connected line of strong points from sea
to sea, or from the sea to the impassable barrier of neutral territory.
Mounted troops are therefore doomed to inaction in their most important
sphere, until the lines have been breached and the enemy is forced to
retreat, and the opportunities for delivering flank attacks are
meanwhile confined to the infantry, and will be due to irregularities
in the alignment of the strong points, upon which enfilade fire may be
brought to bear. The second point of difference is the abundance of
time at the disposal of commanders for developing and rehearsing
elaborate systems of attack and defence, and for obtaining detailed
plans of the hostile works, through continuous reconnaissance by the
Air Service. In most countries there must be, of necessity, a
prolonged period of inactivity on both sides in a Position War, owing
to the severity of winter conditions, or to the occurrence of the rainy
season, and during that period it will seldom be possible to penetrate
the enemy's main defences on such a scale as to bring about the grand
offensive. But this is a period of inactivity in appearance rather
than in fact, for no defensive system is ever perfect, no strong point
but needs further consolidation, new trenches are constantly
constructed or improved, and fresh areas are covered with wire
entanglements. Guns of all calibres, underground mines and light
mortars are ever at work, demolishing, wounding, and killing, while
lachrymatory and asphyxiating shell-fire is to be expected at all
times. On a smaller scale, snipers on both sides have a daily bag, and
{82} observers are ever at their posts noting every change, however
insignificant, and every new piece of work; "listening posts" are
detecting hostile plans, while patrols are collecting information and
raiding parties are reconnoitring, destroying defences, and inflicting
losses, it being the first principle of a raid that it should result in
grea