Just what service this board has performed is in the keeping of the
government. But that it has been a distinguished service we may not
doubt. Seated in their headquarters at Washington, their minds centred
upon the various problems of the sea which the war brought forth, they
have unquestionably exerted a constructive influence no less vital than
that played by the officers and men of the navy on the fighting front.
Only one announcement ever came from this board, and that was when
William L. Saunders gave forth the statement that a means of combating
the submarine had been devised. This early in the war. Doubt as to the
strict accuracy of the statement came from other members of the
Inventions Board, and then the whole matter was hushed. Mr. Saunders
said nothing more and neither did his colleagues.

But whether emanating from the lucubrations of Mr. Edison's board, or
wherever devised, we know that the American Navy has applied many
inventions to the work of combating the under-sea pirate. A type of
depth-bomb was developed and applied. This is one of the most efficient
methods of beating the submarine that has yet been found. Explosive
charges are fitted with a mechanism designed to explode the charge at a
predetermined depth below the surface of the sea. The force of the
explosion of a depth charge dropped close to a submarine is sufficient
to disable if not sink it, and American boats have been fitted with
various interesting means of getting these bombs into the water.

Smoke-producing apparatus was developed to enable a vessel to conceal
herself behind a smoke-screen when attacked by submarines and thus
escape. Several types of screen have been invented and applied in
accordance with the character of the vessel. After a study of the
various types of mines in existence, there was produced an American mine