8371. Salmon, C., and Creffield, H. J. April 7. Order apparatus.-Relates to improvements in the electric order apparatus for ordnance described in Specifications No. 29,422. A.D. 1904, and No. 4741, A.D. 1905, and consists in the provision of a transmitter comprising a group of electro-magnetic switches situated in a central position so as to equalize the drop of potential occurring in the wires leading to the various instruments. The system shown in Fig. 2 includes range and deflexion transmitters A', A<2>, and receivers A<3>, A<4>, respectively, a " fire-control " switch A<5>, and the intermediate transmitter W. The switch A<5> is employed to reverse the current in the field coils a<x>, and to influence a magnetized bar to give warning of the use of the apparatus ; it also reverses the current in the armature coils a<8>, a<9>, and hence does not affect their direction of rotation. The intermediate transmitter comprises two switches P, Q in the fire- " control " circuit, and similarly arranged groups of switches A, B, C, D, J, K, corresponding to the range and deflexion transmitters respectively. The armatures of the magnets P, Q are connected to the negative and positive mains respectively, and normally rest in contact with stops Px, Q<x>, which are each connected to the base of the other magnet by conductors i<5>, i<6>. Closure of the switch A<5>, however, completes the circuit through the coils, and causes the armatures to be attracted into contact with the cores, thus reversing the polarity of the switch bases, and hence reversing the direction of current through the field windings ax with which they are connected by conductors 1, 2. The bases of the switches A, B, J are connected to the base of the switch P by a conductor l, and the bases of the switches C, D, K to that of the switch Q. The coils of the switches A, B, C, D are connected at one end by wires a<1>, b<1>, c<1>, d<1> to corresponding segments a, b, c, d of the rotary switch A<X>, and at the other end to the coils of the switches J or K as shown, and thence to the negative main. The central contact-ring x of the rotary switch is connected to the positive main through a wire x<1>. The armatures of the pairs A, C ; B, D ; J, K are in electric connexion, and communicate by wires 3, 4, and 5, respectively, with the rotary armature coils a<8>, a<9>, as shown. The action of the apparatus is as follows:-The switch A<5> being open, and the switch-arm A<x> being in contact, say, with the segment a, current passes from the positive main to the ring x, then to the segment a, and by way of the wire a<1> to the coils of the switches A, K, and thence to the negative main. The corresponding armatures are attracted, so that current flows through the wire i<a> to the base of the switch P, which is in connexion with the base of the switch A, through the cores and armature of the latter, and by way of the wire 3 to the coils a<8> of the various instruments, returning through the wire 5 to the armature of the switch K. This being also attracted completes the circuit through the cores and base and the base of the switch Q to the positive main. In other positions of the rotary switch the action is similar, a step-by-step rotation of the armatures of the transmitting and receiving instruments being effected, as described in the Specifications cited above.