EE Ds: 1 
without the bended iteel fpring, 
and therefore I did not put it to 
that which I made ufe of. 
Fig; II. The {mall tube or mea- 
fure, with the brats focket, {lider, ’ 
and {prings, all taken afunder to fee 
their fhape. The fcrew ¢ under 
the elaftic piece g, is to be fixed to 
the under part of the fhoulder of 
the brafs focket (at g, in Fig. Il,), 
to fix the elaftic piece g to it.~ 
The pin éfupported by the piece a, 
and pafling through a hole in the 
under part of the fhoulder of the 
focket, enters a cavity made in the © 
under fide of the brafs flider, when 
this flider is drawn out as in Fig. I. 
and thus ftops its coming out en- 
tirely, ms 
U 4 Fig. IV. 
