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COMMENDED ESSAY, 1893 . 
(3.) Uncontrolled or mechanical mines, those which explode when 
struck by friend or foe. These are, of course, very dangerous, and 
impossible to use in a channel where there is any friendly traffic. 
They are always ready, cheap, simple, and certain, but seldom used, 
except to block an enemy’s port. 
The general idea of submarine defence which will be met with will 
probably be modelled on the following :— 
A main mine-field of observation and electro-contact mines with 
advanced guards and reserves of either or both, through the whole 
system a friendly channel defended entirely by observation mines. 
Mines are, of course, a great adjunct to the defence, especially in 
the case of a channel. 
(3.) The Electric Light .—This is a great adjunct to night operations. 
In the Crimean War a search-light on a small scale, produced by a 
Yoltaic battery, was used; but this was a mere toy. The dynamo- 
electric machine, since introduced and perfected, with the Mangin 
reflector, throws a light by which, in clear weather, small objects can 
be clearly discerned at upwards of a mile (steam or smoke at a much 
greater distance), but in mist or fog the ray is useless. 
The balance of advantage in employing the light is with the defence. 
The fact that the Suez Canal is now navigated by its means proves 
nothing as regards ordinary channels. The light is most efficient 
when external to the point sought to be protected, and this is more 
easily accomplished on shore, though special vessels should be em¬ 
ployed to work the attack lights whilst the main fleet remains in 
darkness. Good practice can undoubtedly be made from shore bat¬ 
teries by employing the light in connection with the position-finder or 
depression range-finder, whilst fair practice can be made at a ship 
showing her light. Also a shore light thrown full on a ship renders 
navigation extremely difficult. On the other hand, ships’ lights will 
be of great use to them in detecting counter torpedo-boat attacks. 
Attacking ships and boats should be coloured dull black. 
(4.) The Torpedo .—Like mines, torpedoes first came prominently 
into notice during the American Civil War. Their introduction has 
tended to increase the superiority of the fortress. Some naval officers 
hold that they are quite as formidable to the attacking ships as the 
artillery fire of the fortress. They may be divided into two categories : 
(1) Those fired from the shore ; (2) those fired from a ship. The 
former are incompatible with any except observation mines, and the 
range is limited. The latter have in connection with the boat an 
unlimited range, and counter torpedo-boat attacks are a great obstacle 
to the attack, especially in dusk, mist, or smoke. The fear of them 
would prevent ships from anchoring. 
The best protection against torpedoes was at first thought to be in 
sub-dividing the ship into numerous small compartments, but this plan 
was soon seen to be futile. Then wire nets were suspended from long 
booms projecting from the ship’s side, and these are at present in use. 
They, however, are a most cumbrous appendage and liable to foul the 
screw, moreover torpedoes are now made that will cut through any 
