480
EXPOSITION AT VIENNA.
Werner Siemens, of Berlin, I have been furnished with drawings of this apparatus which are here presented.
A shows the external appearance of the apparatus at an intermediate station, the arms a , a 1 of the semaphore being
a, a)
worked by the cranks h, b 1 . The arm a gives the signal for up, and the arm a 1 for down-trains. The crank c is used to turn a magneto-electric apparatus in the box, from which currents are transmitted in one direction or another, accordingly as the commutatoi; knob or plunger d or d 1 is pressed down. The discs shown on the face are controlled by the current, and