SUMMARY OF CURRENT RESEARCHES RELATING TO 
584 
of a very strong dove-tail shaped slide F, so hollowed out in its up pel- 
part that it affords tho requisite room for the spiral spring W. I he 
Fig. OS. 
under part of F is pierced, and conceals the very long nut for the micro- 
meter-screw M. Contact ensues between the hard-tempered extremity 
