125,216. Green, H. April 11, 1918. Mine signalling systems; order apparatus. - A mine signalling system comprises a plurality of shafts adapted to be rotated step-by-step electro-magnetically and released electro-magnetically through the operation of a pair of cancelling relays, and a selecting switch operated step-bystep electro-magnetically to place the actuating magnets of the shafts in circuit successively. The actuating magnet of the selecting switch is controlled by a series of timelag relays in such a manner that a pause between two series of actuating impulses allows this magnet to be energized to step the selecting switch-arm to its next position. Each of the operated shafts carries a contact-arm controlling the circuit of its releasing magnet and a contact-arm controlling a series of lamps. The contacts of the cancelling relays are connected so that the " action " signals are cancelled at the beginning of the wind and the " cautionary," " special," and " destination " signals are cancelled at the end of the wind. Switches 1, 2, and 3 are operated successively by stepping magnets 6 the circuits of which are controlled by a selecting switch 11 the arm 12 of which is stepped around by a magnet 13. The circuit of the magnet 13 is controlled bv a series of time-lag relays 14, 15, 16 and 17. The contact arms 4 and 5 of the switches 1, 2, and 3 are released by electro-magnets 7 the circuits of which are controlled by cancelling relays 8 and 9 and the contact arm 5. In the arrangement shown, when the arms 4 are in positions to energize " action " signals, the corresponding arms 5 engage contacts 30, 31, 34, or 35 connected by a lead 40 to the front contact of the relay 8, and these signals are cancelled at the beginning of the wind. When the arms 4 are in positions to energize " cautionary," " special," or " destination " signals, the corresponding arms 5 engage contacts 33, 36, 37, 38, 39 or 42 connected by a lead 41 to the back contact of the relay 8 and these signals are cancelled at the end of the wind. The signalling impulses are received by a master relay 18, the armature 21 of which is operated to place a stepping magnet 6 and the time-lag relay 14 across the battery. The magnet 6 moves the contact-arms 4 and 5 one step for each impulse received, while the magnet 14 aperates to close the circuit of the magnet 15 which controls the magnet 16, and the magnet 16 controls the magnet 17. The magnets 16 and 17 control armature 16<1>, 17<1> in the circuit of the magnet 13. After the arms 4 and 5 of the switch 1 have been stepped around to their desired positions by the first set of impulses received by the relay 18, a pause is made which allows the relays 14 to 17 to de-energize. The deenergization of the relay 16 before the relay 17 allows the armature 16' to complete the circuit of the magnet 13 to step around the switch-arm 12 and this circuit is broken bv the de-energization of the relay 17. The next set of impulses operates to set the arms 4 and 5 of the switch 2 after which the above operation is repeated to operate the switch 3. The cancelling relay 8 operates before the relay 9 so that the armatures 50 and 51 are operated before the armatures 52 and 53. The arms 4 control the circuits of a set of signal lamps. Specification 18780/14 is referred to.