85 
1917-18.] Studies in Clocks and Time-keeping. 
inor contact. One excellent feature of the clock is the ease with which 
its adjustments can be varied. The intensity of the maintenance can be 
varied by shifting a counterpoise along one of the arms of the crutch-piece, 
and the position with respect to the vertical at which the pendulum picks 
up the crutch can be changed by changing the angle between this arm and 
the contact arm of the crutch. The arc through which the crutch moves 
in following the pendulum from the position of its upper to its lower stop 
Forces on Kinetic reactions 
pendulum. of pendulum. 
Fig. 5. 
could be changed by shifting one of the stops, but in the actual clock this 
can be done less readily. These opportunities for variation make the clock 
of peculiar interest for theoretical investigation. Not least useful of its 
features is the fact that contact is made and broken directly by the 
pendulum. When examined with the microchronograph, it is found that, 
in consequence, the signals sent out are entirely free from certain 
accidental anomalies which present themselves in the signals of Riefler 
and Synchronome, and which must be ascribed to the indirectness of the 
signal contacts of the two last. 
