un defence of
9.2-in. and 6-in. guns pushed well forward, assisted by
position-finders, mine-fields and torpedo stations, and with some gun
defence of inner waters. Subject to improvements in patterns of guns and
mountings--of which the most important has been the substitution of
barbette mounting and shield for the recoil mounting described
above--this system held the field up to 1905, when, partly as a result
of the experience of the Russo-Japanese War, and partly owing to the
alteration of the naval balance of power due to the destruction of the
Russian fleet, both the scale and system of defence were very
considerably modified.

We can now consider another branch of defence, which was evolved _pari
passu_ with the automobile torpedo, and was therefore almost
non-existent in 1885. In this year the boats specially built for
carrying torpedoes were little more than launches, but in the next five
years was developed the type of first-class torpedo boat. This, while
seaworthy, was limited as to its radius of action by the small amount of
coal it would carry. But with a possibly hostile coast only a few hours'
steam away, and with foreign harbours thronged with torpedo craft, it
became necessary for the British government especially to consider this
form of attack and its antidote. It was obvious that in daytime and in
clear weather such an attack would have little chance of success, also
that in no circumstances would torpedo boats be able to damage fixed
defences. Their best chance was attack by night, and the only form of
attack was that referred to above as "running past," that is, an attempt
to evade the defences and to attack ships or docks inside. The light
draught of torpedo boats and their comparative invisibility favoured
this form of attack.

To meet it the first requirement was some form of illumination of the
defended channel. Experiments in the attack and defence of defended
harbours took place at Gosport in 1879 and 1880, at Milford Haven in
1885, at Berehaven (by the royal navy) in 1886, at Langston Harbour in
1887, and a series at the Needles entrance of the Isle of Wight up to
1892. During the course of these experiments various methods of
illumination were tried, but by far the best was found to be the light
from an electric arc-lamp of high power projected by powerful
reflectors. At first these were used as concentrated beams forming a
pencil of light with an angular opening of about 2 deg. to 3 deg.