Page:Popular Science Monthly Volume 89.djvu/697

 Popular Scicucc Monthly

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��Two Mines Which Make Marine Warfare More Terrible

THE accompanying illustrations show- two ditTercnt types of mines whicii have been devised since the great war started. The mine with the periscop;' attached is said to be the latest Teuton lure for British skippers who are seeking the $2,500 reward offered by the British Admiralty for ramming a submarine. Not long ago one of these periscope mines was sighted in the English channel by a steamship captain. Taking it lor the periscope of a submarine the captain ordered all speed ahead, in an attempt to ram what he thought to be a lurking U-boat. As he was fast approaching it he noticed, to his bewilderment, that it did not move. He became suspicious and when almost upon the periscope, ordered his pilot to give it wide berth. Later he in\'esti- gated cautiously and found that the periscope was at- tached to a huge mine.

The other mine is the invention of Giovanni Elia, of Paris, who believes that it is the most effective of any mine now in use. His mine cannot explode by coming in contact with strong tides or striking slight obstructions in the water.

It is anchored, and, when a moving ship comes in contact with it, a shock is produccc which is absorbed entirely by the circular frame projecting from the body of the mine. Under the influence of this shock three screws in the firing mechan- ism are cut through.

In the meantime the mine, having come in contact with the vessel, turns, under the effect of the friction of the hull of the ship. This turning movement cocks a striker and then releases it, causing the expjosion. The mine can be manipulated and transported without danger prior to its being submerged.

����Above: The peri- scope mine — the Teuton lure for British skippers. The periscope is merely attached to the top of an anchored mine. At left: A mine which cannot ex- plode unless struck by the hull of a ship. The circular frame is a shock absorber

��The Deepest Known Place in the Ocean

THE greatest ocean depth known is 5,269 fathoms, or 31,614 feet. It is about seventy-five miles southeast of the Island of Guam. This figure was ob- tained in 1899 by the U.S.S. Nero when running a line of soundings to locate the Honolulu-Manila cable. The mean depth of the entire ocean is about 2,100 fathoms, or 12,600 feet.

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