the thrower, and 30 to 40 yards may be regarded as the maximum
distance. The _rifle grenade_ is effective up to about 400 yards, and
is generally employed to provide a local barrage or to search cover.
In the latter case, a high angle of descent is used as with mortars or
howitzers.

LIGHT MORTARS.--The _Light Mortar Section_ is an integral part of every
infantry battalion, and although sometimes brigaded for special
purposes the sections normally work with their own battalions. A
section of 2 light mortars, firing 11-lb. bombs, consists of 1 officer
and 20 other ranks, and requires 2 horses and 1 G.S. limbered wagon.
Owing to the high angle of descent the bombs can be fired behind, and
can search, high cover, while the mortars themselves are not very
conspicuous objects and can be {167} readily moved for short distances,
while they "come into action" in 30 seconds. The comparatively slow
flight of the bombs, however, enables the enemy to discover the
location of the mortars, and necessitates the use of expedients to
avoid counter-artillery fire. A maximum rate of 30 to 40 rounds a
minute can be maintained for two or three minutes, if ammunition is
available, and at an angle of 45 degrees a range of 700 yards can be
obtained.

MACHINE GUNS.--"The principal characteristic of the machine gun is its
power of delivering a concentrated volume of fire which can be
sustained almost indefinitely, subject to limitations of ammunition
supply. The ease with which the gun can be concealed in action and its
fire controlled enable advantage to be taken of surprise effect"
("Field Service Regulations," vol. ii. (1921)). The _Machine-gun
Platoon_ is an integral part of every infantry battalion, but in Attack
machine guns are frequently grouped for the purpose of providing
overhead or other covering fire, while in Defence they form, with the
artillery, the framework into which the defensive dispositions are
fitted, and by reason of their fire-power machine guns enable a
commander to economise in the number of infantry allotted to a purely
defensive _role_. The ranges are those given above for rifles and
Lewis guns, and the rate of fire is about 20 times that of a rifle,
while 1,500 to 2,000 rounds may be fired continuously at a moment of
need.

MOUNTED TROOPS

CAVALRY.--The principal characteristic of cavalry is its mobility.
This enables it to attack unexpectedly; to defend with determination
while retaining the power t