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The crown or faw. 
The fpindle to which the faw is faftened. Note, the fpindle 
is to be made fmaller from each end to the middle, that it 
may not touch the barrel but at the upper and lower parts, 
to prevent too much friction in turning. 
The canula or barrel into which the {pindle is introduced. 
The lower part of the canula' which projects fomething above 
a quarter of an inch, on which the left hand is refted. 
The handle, with a {quare | opening to fit the end of the {pindle. 
The knob of the handle, which fhould be made of ivory. 
The nut to fcrew on the end et the fpindle to keep the 
handle on. 
The end of the canula, formed {quare to fit the wooden handic 
when ufed as a trephine: : ta fe 
; The wooden handle fitted to receive the canula and {pindle ; 
when ufed as a trephine, the upper fide is See to 
admit the nut. 
The center-pin of the crown or faw. r 
The key, one end of which is made to fit the center-pin, and 
the other, which is forked, to fit the cavity in the top of 
the nut. 
PLATE 
——- Se OO — ee 
