. The railroad and engineering journal . of an enemys ship. He may mistake a friendly for ahostile craft, but he will never mistake its position, sincethe blow from a passing vessel will at once indicate tothe shore station that it is above the mine. Such minesmay be arranged so as to be fired at will or the one case the blow closes an electrical circuit andsignals the fact to the observer by dropping a shutter orringing a bell, leaving it to his will whether or not to ex-plode the mine ; or the signaling current may, instead,be made to switch in a powerful firing battery, and
. The railroad and engineering journal . of an enemys ship. He may mistake a friendly for ahostile craft, but he will never mistake its position, sincethe blow from a passing vessel will at once indicate tothe shore station that it is above the mine. Such minesmay be arranged so as to be fired at will or the one case the blow closes an electrical circuit andsignals the fact to the observer by dropping a shutter orringing a bell, leaving it to his will whether or not to ex-plode the mine ; or the signaling current may, instead,be made to switch in a powerful firing battery, and thusexplode the mine in a purely automatic manner. Theadvantages of such a system of mines in a channel or. n3^. L-^ aw uu |uu water way, that must be used by friendly ships and maybe used by a hostile fleet, are too obvious to need men-tioning. An observation ground mine may be converted into acontact mine by the employment of a buoy anchored aboveit, which carries the circuit-closing apparatus, and withwhich it is in electrical connection. Fig. 11 shows sqchan arrangement, the buoy b, carrying the signaling or circuit-closing device, the mine a, containing the fuse andthe explosive. A controllable buoyant mine carries within its case acircuit-closer, an electrical fuse and the explosive 12 shows, partly in section, the English sphericalmine case—Gibbins—previously referred to. It may beof iron or steel, in two hemispheres, and bolted togetheras shown. The upper hemisphere is provided with asunken eye-bolt a for purposes of handling. The lowerhemisphere has the loading-hole, b, into which is insertedand bolted a cylindrical case, c, containing the circuit-closer, the fuse a
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectrailroa, bookyear1887
