as regards common practise in such matters, would naturally make a point of cutting all wires that fall in his path. From these and other obvious considerations, it is evident how simple and yet how perfect a means of protection such a system provides. I will now proceed to explain the manner of application. The bell used differs from the ordinary, only in the arrangement of its external connections.
Fig. 56 A.
[Fig. 56 A] represents a single-alarm circuit. When contact is broken externally, there is a closed circuit in which are the battery and bell magnet coils.
Consequently the armature is drawn away from the contact stud, close up to the electro-magnet, and is held so. When a break occurs, the armature flies back, completes the local circuit, and rings so long as the external circuit remains broken. There is a switch for use when the alarm is not required.
Fig. 56 B.