T22 



TORPEDOES. 



the metal tube h, is soldered on to a copper ring 

 (p) encircling the bar (k) and insulated from it. 

 The insulated conducting wire /passes through 

 a hole in the tube h, and its bared extremity 

 is attached to a binding screw (q), in connec- 

 tion with an insulated brass band, let into an 

 ebonite ring, which is fitted around a hollow in 

 the brass tube. When it is designed that the 

 fuse shall be kept out of circuit till the moment 

 of firing that is, to explode solely from the effect 

 of an outside shock the electric cable from the 

 firing battery is connected with the insulated 

 wire e, the other pole of the battery being to 

 earth ; and the wire / is attached through an 

 insulated conductor to one pole of the fuse while 

 a metallic connection is arranged from the other 

 pole of the fuse to earth. Firing the fuse only 

 requires to bridge over the space between the 

 copper -ring (p) and the brass ring (q), with 

 which the conducting wires are respectively con- 

 nected. A vessel striking the top of the appara- 

 tus in any direction would effect this, as it would 

 ;jar the bar (k), and by action of the universal 

 joint (i) some part of the copper ring (p) would 

 be brought into contact with the brass band (q), 

 thus completing the circuit. When it is desired 

 that the fuse should be arranged in permanent 

 connection with the circuit the combination would 

 be as follows : One pole of the firing battery be- 

 ing to earth, the 6ther is connected by cable 

 with one pole of the fuse, the other pole of the 

 fuse being placed in metallic connection with the 

 wire e, while the wire / is put to earth by be- 

 ing connected with the metallic portion of the 

 case (a). A shock from above would at once 

 bridge over the space between the rings (p and 

 q), firing the fuse ; or, on the other hand, the mine 

 could be exploded at will from the mining case- 

 mate by connection with the firing box. 



In England and Germany the circuit-closer is, 

 in most cases, a separate attachment. The great 

 objection to it is that the first object of an en- 



being one hundred feet distant from the junction 

 box, and the groups one hundred feet from each 

 other. From the triple junction boxes issue sin- 

 gle ones, which are joined together at the grand 

 junction box into the multiple cable. This is 

 carried ashore into the mining casemate, which 

 is the firing station, and, passing to earth, com- 

 pletes the circuit. It will be seen from this de- 

 scription that each of the separate cores of the 

 cable carries the electric current to a triple group, 

 so that at no time can fewer than three be dis- 

 charged from the shore. Any one torpedo, how- 

 ever, can be independently exploded by concus- 

 sion from a passing vessel. The touch of a ship 

 rings a bell m the mining casemate and breaks 

 the circuit for five seconds, thus preventing the 

 two nearest companions to the discharged mine 

 from being exploded by mechanical shock from 

 the disturbed water. If, on the other hand, the 

 touch of a side or keel has possibly been too 

 light to discharge a mine, the warning ashore 

 gives an opportunity for the use of the firing box 

 in the mining casemate to discharge the whole 

 group of three. The fact that a group of mines 

 can be made perfectly safe for the passage of 

 friendly ships or merchant vessels is a point of 

 great importance. The occasional failure of a 

 mine to explode by contact, as might occur when 

 touched by an outrigger, would be remedied by 

 a warning to the electrician and his consequent 

 action. In case of heavy fog or the smoke of 

 battle hiding ships from view, thus preventing the 

 tracking of them from theodolite stations on a 

 chart, such reports from the torpedo itself would 

 be of the greatest value, guiding action as to the 

 policy and time of firing any special group. It is 

 this combination of automatic action with power 

 to communicate results to the shore station which 

 constitutes the crowning triumph of the subma- 

 rine mine. For example, hostile vessels are ap- 

 proaching the torpedo field. The commanding of- 

 ficer in the mining casemate suspends the auto- 



ARRANGEMENT OF MINES. 



emy attacking a harbor would be to explode the 

 mines in his front, or, failing in this, to get 

 hold of and carry off the circuit-closers, and 

 break the cable connections, thus rendering the 

 charges unexplodable. This would be much easier 

 to accomplish if the apparatus were detached. 

 The priming fuse generally used consists of ful- 

 minate of mercury, duplicated in several com- 

 partments. The fuse fits into a receptacle made 

 to hold one pound of dynamite, which consti- 

 tutes the main percussive charge to the whole 

 mass. The unit of arrangement which deter- 

 mines the distribution of mines on the hydro- 

 graphic plot is a grand group of twenty-one^ sub- 

 divided into seven triple groups, as may be seen 

 illustrated in the diagram. Each minor group 

 is set in the shape of a triangle, the torpedoes 



matic action of any section, or of a grand group, or 

 of several groups. The observers at the theodolite 

 station or stations engaged in tracking the course 

 of the enemy's ships with reference to the tor- 

 pedo locations, report the facts to the mining case- 

 mate. The electric current may be reserved 

 from the circuit till several ships of the fleet, 

 unwarned by explosion, are destroyed simulta- 

 neously when they reach favorable stations on the 

 torpedo field. Strategy is thus made possible in 

 the use of submarine mines. From first to last 

 each step in the torpedo system is infallibly 

 tested, and the testing never ceases. 



Every detail of the complex apparatus can 

 be examined from the mining casemate, and a 

 fault located by electricity. The testing be- 

 gins with the storage of material. The multiple 



