338 Improved Method of Constructing 
collar C, Fig. 14, and exactly fit the holes they pass through in 
the collarG. By this means the two arms forming the pallet- 
frame are held together, and firmly fixed between the collet C 
and the collar D, and consequently attached to the verge A A. 
It is to be observed, that the screws X and Y must not be screwed 
so tight that the regulating screw, H, has not power to overcome 
the friction of the arms of the pallets between the collet C and the 
collar G, for in that case the whole intention of the jointed 
pallet-frame would be frustrated. To enable the arms to open 
and close, there are two circular notches in the same places in 
each half of the pallet-frame, concentric with the centre, (see 
Figs. 11, 12, and 13,) through which the two screws X and Y, 
Fig. 15, pass, and the quantity of motion of the arms is deter- 
mined by the length of the circular notches. The two studs 
F and F, Fig. 15, through whith the regulating screw, H, 
passes, are connected with the upper arms of the pallets by 
pivots, which pass through them, and are held in their places 
with collets and screws.—See Fig. 14. Care must be taken 
not to screw the studs so tight as to prevent their turning on 
their centres, otherwise the regulating screw, H, will be bound. 
This screw, H, being of two different threads, the one coarser 
than the other, thereby producing a very fine motion, has the 
effect, when turned in one direction, to open the pallets; and 
turned in the other, to close them. 
The great advantages in this mode of construction are, Ist, 
That the rests of the pallets are correct portions of circles, the 
centre of which circles is the centre of motion of the axis of the 
verge, and the pallets move in the same circles, and, conse- 
quently, there will not be any recoil in the escapement. 2d, 
That the pallets must be of equal thickness, and consequently 
the drop the same on both. 3d, That the pallets may be made 
perfectly hard, if properly treated, without risk of altering their 
shape: and should a pallet be spoiled by any accident in hard- 
ening, or a flaw or imperfection of any kind be discovered, 
another exactly similar is easily made to replace it out of the 
original ring. When the pallets are made out of the same piece 
of steel as the arms of the frame, it is difficult to preserve their 
