Gruspp—Form of Electrical Control for Driving Clocks. 35 
metallic part of the apparatus) be connected to one of these brass 
bands, the accelerator is brought into action ; while, if the other be 
connected to “ earth,” the retarder is brought into action. 
Close beside this insulated disc, and strung loosely on the same 
spindle, is an un-insulated wheel a, a, with twenty V nicks or cuts 
on its edge. 
There is an arrangement by which a small amount of friction 
can be introduced in the revolution of this wheel on the spindle ; 
and this can be regulated with great nicety. 
Two spring contacts s, s’, are so arranged on this toothed 
wheel that, under ordinary conditions, neither of the springs 
forms contact with the metal bands on the insulated disc; but a 
very slight motion of the toothed wheel on its spindle, in either 
direction, will cause contact to be made between one or the other of 
the springs and one or the other of the metal bands, and, in doing 
so, will bring either the accelerator or retarder into action. 
Over this wheel is mounted a lever with a V tooth, which fits 
into any of the V cuts which happens to be exactly under it. 
This lever is actuated by an electric-magnet, through which 
an instantaneous current passes once a second from the regulating 
clock, which may be any distance away. 
