Our power of defending the Thames and Medway from the
shore, and without the aid of ships, was tested on Monday night, when four hired steamers, representing a hostile fleet, attempted to raid the Port of London. At 9 o'clock, the Colonel commanding at Sheerness received information by signal that the enemy were approaching. Immediately the electric search-lights at Grain Fort, No. 1 Bastion, and Barton's Point were turned upon the water, and by their aid the enemy's flotilla was discovered approaching by the Medway -channel. A fierce cannonade was at once opened upon them and kept up by the forts. The steamers steamed on, however, till they entered " the mine field "—a space of water sown broadcast with torpedoes—and were therefore declared to have been blown up. Of course, this does not prove that London can certainly be protected; but it does demonstrate the efficacy of the electric light in making narrow pieces of water as easily defensible by night as by day. But even without this, London could never be attacked by water. The river at Gravesend could be barricaded like a street by sinking a dozen big liners and -filling up the interstices with hoys and hay-boats.