st be corrected
for our purpose. We will take it for granted that all the seats _a_ are
of precisely the same height, measured from _B_, and that a watch plate
placed in the jaws _C_ will be held exactly parallel with the said bed
_B_. We must next provide two pillars, shown at _D E_, Figs. 109 and
111. These pillars furnish support for sliding centers which hold the
top pivots of the escape wheel and pallet staff while we are testing the
depths and adjusting the pallet stones. It will be understood that these
pillars _D E_ are at right angles to the plane of the bed _B_, in order
that the slides like _G N_ on the pillars _D E_ move exactly vertical.
In fact, all the parts moving up and down should be accurately made, so
as not to destroy the depths taken from the watch plate _A_. Suppose, to
illustrate, that we place the plate _A_ in position as shown, and insert
the cone point _n_, Figs. 109 and 112, in the pivot hole for the pallet
staff, adjusting the slide _G N_ so that the cone point rests accurately
in said pivot hole. It is further demanded that the parts _I H F G N D_
be so constructed and adjusted that the sliding center _I_ moves truly
vertical, and that we can change ends with said center _I_ and place the
hollow cone end _m_, Fig. 112, so it will receive the top pivot of the
pallet staff and hold it exactly upright.

[Illustration: Fig. 110]

[Illustration: Fig. 111]

[Illustration: Fig. 112]

The idea of the sliding center _I_ is to perfectly supply the place of
the opposite plate of the watch and give us exactly the same practical
depths as if the parts were in their place between the plates of the
movement. The foot of the pillar _D_ has a flange attached, as shown at
_f_, which aids in holding it perfectly upright. It is well to cut a
screw on _D_ at _D'_, and screw the flange _f_ on such screw and then
turn the lower face of _f_ flat to aid in having the pillar _D_
perfectly upright.

DETAILS OF FITTING UP ESCAPEMENT MATCHER.

It is well to fit the screw _D'_ loosely, so that the flange _f_ will
come perfectly flat with the upper surface of the base plate _B_. The
slide _G N_ on the pillar _D_ can be made of two pieces of small brass
tube, one fitting the pillar _D_ and the other the bar _F_. The slide _G
N_ is held in position by the set screw _g_, and the rod _F_ by the set
screw _h_.

[Illustration: Fig. 113]

[Illustration: Fig. 114]

The piece _H_ can be permanently attached to the r