334 A7r. mudge cn the ConflruSiion 
hold, fill the hole of the metal audits handle with water, 
to prevent the evaporation of the moifture, and the con- 
fequent aclhefion between the fpeculum and polifher, and 
let the whole reft in this ftate two or three hours: this 
will produce ah intimate contact between the two, and 
by parting, with any degree of warmth they may have 
. acquired by the vicinity of the operator, they will grow 
perfectly cold together. 
- By. this time you may.pufh out the cork from the po- 
lithe r, to difeharge the water, and give the metal the pa- 
. .xabolic figure in the following manner. 
Move the metal gently and ilowly at firft, a very little 
round the centre of the polifher (indeed after this reft it 
will move ftiflly) then increafing by degrees the dia- 
meter of thele ftrokes, and turning the metal frequently 
round its axis, give it a larger circular motion, and 
this without any preflure but its own weight, and 
holding it loofely between the fingers: this manner 
of working may iafely be continued about two mi- 
nutes, moving yourfelf as ufual round the block, 
and carrying the round ftrokes in their increafed 
and largeft ftate, not more than will move the edge 
of the metal half an inch or fiv^-eighths over the took 
The fpeculum muftnot all this while be taken off from 
the polifher; and confequently no ffefh putty can be 
added. 
