Memorandum, German Traps and Mines

2nd Br [S.S. 734]. Ia/54195. 60 8 GERMAN TRAPS AND MINES. (Supersedes Ial31737, German Ruses.") 1. ABANDONED POSITIONS. Attention is drawn to the practice of the enemy, when making an organized withdrawal, of leaving certain positions, dug-outs, dumps, etc., mined, the firing arrangements being such that the charges are exploded after the pos sition has been occupied by our own troops (see S.S. 163, Hints on Reconnaissance for Mines, 2. LIKELY TRAPS. The following should be regarded with special suspicion until investigation has been carried out by experts - Attractively furnished dug-outs. Dug-outs under roads. Single houses left standing when others have been destroyed. All new work, or new trench or other equipment, in the midst of weather-worn ground AND or articles, e.g., recently disturbed soil, new metalling, new trench boards SERVICE" Souvenirs, such as helmets, shells, badges and bayonets, left in conspicuous positions. Articles sticking in the ground, such as stick grenades or shovels. 3. METHODS OF FIRING. German traps and mines may be classified under the following headings according to the nature of their firing arrangements. (a) Delay action fuzes.-The action of these fuzes depends on the eating away of a wire by a corrosive solution. The delay may be any time up to one month. Two patterns are known: - (i.) Automatic detonating device.-This - device differs from any other German fuze and can be easily identified. It is employed with bulk charges and placed in the explosive. For description see S.S. 733, German Automatic Detonating Device.' (ii.) 1917 long delay action fuze.-This is a counterfeit 1904 pattern German gun fuze and can only be identified by the fact that the gaine is painted red, but when screwed into a shell is indistinguishable from the ordinary fuze. For description see S.S. 732, 1917 German Long Delay Action Fuze for Demolition Purposes." It is primarily intended for destroying guns and ammunition. The 1904 fuze is principally used with 10-cm., 13-cm. and 15-cm. gun shell and with 15-cm. and 21-cm. howitzer shell. It is not used with any field artillery shell (see S.S. 306, " Notes on German Fuzes," page 68). These fuzes are absolutely silent and require no connections outside the charge. New work or signs of the ground having been disturbed will probably be the only indications of their presence. (b) Clockwork devices.-These are of complicated manufacture and will probably be rarely met with. They may possibly be discovered by the ticking. (c) Percussion devices.-The percussion device may be set in action by treading or pressing on a board hidden under earth or by pressing against a railing, etc., when a safety pin will be with drawn, releasing the spring of a spring lighter, or a striker may be driven into a detonator. (d) Electrical devices.Electrical devices depend on a pull on a wire or pressure on some article completing a contact. (e) Mines fired electrically from a distance.-This method is chiefly applicable to bridges and billets used as H.Q.s, where telephone wires can be utilized for the firing circuit. These mines can be fired at will by the enemy at any moment so long as the wires remain uncut. As a rule, suspicious wires should be cut at once, but care must be taken not to cut taut wires (these may be found mixed up with slack telephone wires) as they may be simply supporting a weight, which, if the wire is severed, will drop on and ignite a detonator. Wires, if cut, should not be pulled out, but the cut ends should be turned away from each other nd carefully marked, both ends of each wire alike, so that experts when they arrive can investigate, trace and remove the charge 4. TYPICAL EXAMPLES OF TRAPS. 1. Dug-outs. (a) A shovel stuck into the side of a dug-out between the timbers; when the shovel is removed, it pulls a wire which explodes mine the (b) A French stove with stove-pipe dismantled one wire attached to leg of stove and the other to stove-pipe near by. When the stove-pipe is picked up, a mine is fired. (c) A charge of 2,000 lbs. Perdite in a seemingly dead end of the gallery of a dug-out and connected to ordinary telephone wires. Face of the gallery made up to look like undisturbed ground with pick marks on it.