594 
BRIEF CONSIDERATIONS ON COAST DEFENCE. 
be created. Perhaps there is no more suitable employment for mines. 
It is obvious that the sites should be as high as possible, within 
reasonable limits; as the range will be longer at which it will be neces¬ 
sary for ships to engage with effect, and while the ship offers the 
greatest possible target the land battery affords the least. A shell, 
striking the face of a battery in a direction more ascending than nearly 
parallel to the terreplein, would be ineffective. A site of 100 feet above 
the sea-level would require to be attacked at a range of 1490 yards; one 
of 200 feet, at 2070 yards ; of 300 feet, at 2530 yards. Hence, except 
where the heavier quick-firing guns are mounted and the risk must be 
incurred, guns, on all sites of less than 200 feet, should be mounted on 
disappearing mountings; and, on very low sites below 50 feet, these 
mountings are a necessity. Disappearing mountings neutralise the 
advantage of an enemy's quick-firing guns, which see no target except 
at the moment of firing. No water area, however limited, should be 
defended by one gun only. 
Where sites are not less than 250 feet above the sea-level, it is un¬ 
necessary that the armament of the defenders should be equal that of 
the attacker, provided, that the guns are heavy enough to strike the 
enemy at his fighting range with effect. On lower sites, it is desirable 
that the armament should be equal to that of the enemy, at least. 
If guns on low sites are not mounted on disappearing mountings in 
emplacements properly constructed, so as to be thoroughly protected 
against direct fire, the number of the defender's guns should be in¬ 
creased. 
Assuming the minimum attacking force to be as indicated above, 
the number of guns to be opposed would vary from 20 to 30; and the 
defender should be able to concentrate the fire of an equal number upon 
any spot, from which an attack could be delivered. High-angle guns 
should be additional to this calculation, as they are only effective against 
ships at anchor, or, moving very slowly, or, in a very confined area. 
Palliser shot is of little value against modern armour, and, unless 
really armour penetrating projectiles are supplied, common shell is the 
principal projectile to be employed. Shrapnel may be used against 
lightly-protected or unarmoured vessels. Time fuzes would be unsuit¬ 
able. 
The idea of attacking unarmoured portions of a vessel with one pro¬ 
jectile, and, armoured with another, is illusory; except, when a ship is 
at rest at a short range, a contingency unlikely to occur. 
The fire of heavy guns at night, without search-lights, will not be 
effective. 
Small quick-firing guns and machine guns should not be too closely 
associated with heavy guns for the attack of an enemy. They should 
be placed in position by themselves. Their usual role is for the pro¬ 
tection of mine-fields, of channels not more than 2000 yards wide, of 
shoal water, against torpedo-boats and light craft. They require 
protection against machine, and, light quick-firing guns. 
Mine-fields are employed to block channels and approaches, and, 
could be most usefully employed, in preventing the approach of ships 
within 2000 yards of batteries. Mine-fields should be placed in close 
