it had a duplicate set concealed.--[_Photos. by Illustrations Bureau._]




__________________________________________________________________________
14--THE ILLUSTRATED WAR NEWS, DEC. 30, 1914.--[Part 21]


[Illustration: SUBMARINE LAMPS AS PILOTS: HARBOUR CHANNELS OUTLINED IN
UNDER-WATER LIGHTS.]

We illustrate here a system of submerged lamps for guiding vessels into
port, invented by M. Léon Dion. It consists of a chain of electric lamps
laid under water to mark the navigable channel, connected by an electric
cable controlled from the shore. In time of war, of course, the light
would be switched on only when a friendly vessel was signalled.--[_By
Courtesy of the "Scientific American."_]

[Illustration: COMPRESSED AIR FOR "PLUGGING" HOLED SHIPS: AN INTERESTING
NAVAL EXPERIMENT.]

This method of stopping the inrush of water was tested on the U.S.
battle-ship "North Carolina." An American naval officer wrote: "Its use
will permit us to repair from inside all holes made beneath the
water-line. Strong pressure is exerted in the holed compartment; slighter
pressure, graduated, in those adjacent (shaded darker)."--[_By Courtesy of
"Popular Mechanics" Magazine, Chicago._]