, THE FOUCAULT PENDULUM 453 



bob, detachable from the wire as shown, is stored away wlien not in use 

 leaving the ware coiled up near its suspension. The box likewise is detach- 

 able being mounted permanently on a wooden bracket which in turn is 



Fig. 7 



fastened temporarily by dowel pins and wood screws (hooks would work 

 In place of screws) to a board permanently anchored to the masonry. It 

 is insulated from the blackboard behind. A direct fastening to the wall 



