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]