Submarine Appliances And Their Uses
Deep Sea Diving, &c., &c.

The BELL EQUIPMENT is of four kinds: (#) The Electrical Shore Station, consisting of a BELL, weighing about 2 cwt., fixed to a tripod 21 feet high, resting on the sea bed, and con- nected with Lighthouse or Shore Station by suitable electric cable, (£) Eight Ves sel Equipment. This is a pneumatic bell similar in shape and form to that of the electrical bell, but worked by compressed air, and is lowered into the water from the vessel at periods of fog, and ring- ing usually a number of times corresponding to the number of the Light Vessel as registered by the Government to which it belongs, (c) Bell Buoy. This mechanism is pendant from any deep-sea 10ft. buoy, and is automatic in action, the power being conveyed from the under con- nection between the buoy and the flotation of a sea anchor fixed thereunder. (W) Hand. Bell. This can be lowered from any pier or jetty, and is worked fry hand power. (a) Is specially adapted for rocky coasts. Its radius of sound is reliable up to ten to fifteen miles, and it has been reported at eighteen miles or more. (Æ) is mostly operated on Light Vessels, and has been largely adopted by the United States Government, and is now being installed by the Trinity House, (c) A third application of the submarine signal is made by suspending a submarine bell from an ordinary gas or otfier buoy, and striking it by a mechanism which is worked by the vertical motion of the buoy caused by the action of the waves. The bell in this case is hung about 16ft. below the surface of the water. The difference in movement between the buoy and a sea anchor suspended below it operates the mechanism. (<Z) This is especially for use by those shipping lines, such as cross-channel boats whose voyages are between ports not far distant, and to whom it is of great value as a time-saver. 1 he RECEIVING APPARATUS can best be described as the “ears” of a ship. Tt consists of two tanks about 22În. square, filled with sea water, fastened securely against the side of the skin of the ship, below the water line—one on the port and another on the star- board side, placed at a certain distance from the bow ; this distance is varied according to the shape of each individual ship. Within each box are suspended two specially designed microphones, wholly immersed, and telephone wires are carried from each microphone to an indicator box situated on the bridge, pilot house, or other convenient spot for the navi- gator. On this box arc suspended telephonic ear-pieces or receivers, enabling two observers to listen simultaneously. Bv the simple movement of a switch, the listener can locate the sound and determine whether it is coming from the port or starboard side. As a pro- vision against accident, a second set of microphones, placed in each tank, can be brought into action by moving another switch. The above are the usual forms in which the apparatus is made use of. It is also largely used by the navies of the world for intercommunication between ships, more especi- ally as it is at present the only known method of communicating with a submarine after she has left the surface, and it is of frequent value for communication between ships of a squad- ron, whose Marconi is out of action, where the Admiral of such squadron is using his wire- less for communication with headquarters, in which case any form of lighting signal is im- possible foi fear of betraying the position of the squadron to the enemy. From the humanitarian and economic points of view there can be but one opinion as to the advantages of Submarine Signalling Apparatus, for there is no doubt that it has been in- strumental in saving many lives and much property. 127