Page:Collier's New Encyclopedia v. 09.djvu/168

SUBLIMATION THEORY 134 SUBMARINES in the hot springs and in the gaseous emanations of A'olcanoes, and might furnish certain constituents for ores and other minerals occurring in veins. SUBLIME PORTE. See PORTE. SUBMARINE BOAT, a boat capable of being propelled under the water. The first was probably that constructed by Drebbel, a Dutchman, for James I, and Robert Fulton made an effort in the same direction in 1801. Among recent sub- marine boats the most noteworthy is the Holland submarine torpedo boat. See Submarine Mines and Navigation. SUBMARINE CABLE, a wire, or com- bination of wires, protected by flexible non-conducting waterproof material, de- signed to rest on the bottom of a body of water, and serve as a conductor for the currents transmitted by an electro- magnetic telegraphic apparatus. SUBMARINE MINES AND NAVI- GATION. Submarine mines consist of spherical or cylindrical containers, usu- ally made of steel, and sometimes lined with concrete, filled with a charge of ex- plosives. They are generally anchored in such a manner that they are concealed beneath the surface of the sea, but they are also sometimes allowed to float and drift. They were first used during the American Civil War, 28 vessels being de- stroyed by them. Their use was devel- oped to a very marked degree in the European War, during which they were employed in enormous numbers by all the belligerents. The North Sea was completely inclosed by two mine bar- rages, the first being laid early in the war by the British navy across the Straits of Dover, and the second by the combined actions of the American and British navies. This was an immense barrage, stretching from the Orkney Islands off the north coast of Scotland, to the coast of Norway, a distance of 240 miles. It contained more than 70,000 mines, and covered an area of 6,000 square miles. It is claimed that its com- pletion sealed the fate of the German submarine. Previous to the war, the charge employed was usually wet gun- cotton, and the explosion was brought about by successive detonations of ful- minate of mercury and a small secondary charge of dry guncotton. Frequently A = TORPEDO TUBE B ^ QUARTERS FOH CREW 2 -900 MP MOTORS (DIESEL) 2. -500 HP. ELECTRIC MOTORS SCREWS RUDDERS TORPEDO TUBES 3incK GUN SPACE FOR EXTRA TORPED05 3; nek GUN DIVING RUDDER PERISCOPES C o E F G H I O K L CROSS SECTION OF A MODERN SUBMARINE