REPORT OF MR. ROBERT B, LINES.
477
"trembling-sounder” T, and on the other hand with the manipulator, to be hereafter described. Each of these coils is placed above the centre of a permanent horseshoe magnet, whose poles N, S, touch lightly the exterior surface of the platina, under the indications "occupied,” "free,” and contains a core of soft iron, at the upper extremity of which a light needle, d, g, also of soft iron, vibrates freely between the two poles of the permanent magnet.
The receiver at the intermediate, station B does not differ from that of the terminal station except in that the coil D 1 , giving the signals for the right track (in going from B to A) is placed above the coil G 1 , which gives the signals for the left line of rails.
The manipulator is the same at both stations. It comprises two buttons, M and M 1 , which, when pressed down, move two rods, held by spiral springs. Each of these rods is furnished at its farther extremity with two insulated rectangular pieces of copper R, R 1 , R 1 , R j, placed in front of a series of seven upright metallic springs, m, n, o, 1, p, q, r. The centre spring 1, connected at the bottom with the line wire, touches at the top, when neither of the buttons M, M 1 , are pressed down, upon a screw V, connected to the wire of the "left track” coil G. The six other springs are connected together by metallic bands, two by two, as shown in the cut, and communicate as follows : —
The two inside springs m, r, with the wire of the "right track” coil, D, the two springs n and^> with the copper pole of the battery, and the springs o and q with the zinc pole.
When the right-hand button M 1 is pressed, the copper rectangles at the end of its rod connect the springs l andp, and q and r as shown in the dotted lines of the cut, at the same time breaking the connection between l and v and insulating the former from the coil G, with which it communicated.
In the same manner the left-hand button M, if pressed, would insulate l from G, and connect l with o, and n with m. The effect of this would be, as will be easily seen by tracing the connections, that when the button M 1 is pressed, a positive current will be transmitted on the line L and a negative current through the coil D and the sonnerie T. In pressing the button M, exactly the opposite effect will be produced.