e shown at Fig. 95, we could only
turn the disk _D_ on the screw _b_; but if we enlarge the screw hole in
_C_ to three or four times the natural diameter, and then place the nut
_e_ under _C_ to receive the screw _b_, we can then set the disks _D D'_
and pallets _B B'_ in almost any relation we choose to the escape wheel,
and clamp the pallets fast and try the action. We show at Fig. 97 a view
of the pallet _B'_, disk _D'_ and plate _C_ (seen in the direction of
the arrow _c_) as shown in Fig. 95.

PRACTICAL LESSONS WITH FORK AND PALLET ACTION.

It will be noticed in Fig. 99 that the hole _g_ for the pallet staff in
the lever is oblong; this is to allow the lever to be shifted back and
forth as relates to roller and fork action. We will not bother about
this now, and only call attention to the capabilities of such
adjustments when required. At the outset we will conceive the fork _F_
attached to the piece _E_ by two screws passing through the holes _h h_,
Fig. 99. Such an arrangement will insure the fork and roller action
keeping right if they are put right at first. Fig. 100 will do much to
aid in conveying a clear impression to the reader.

The idea of the adjustable features of our escapement model is to show
the effects of setting the pallets wrong or having them of bad form. For
illustration, we make use of a pallet with the angle too acute, as shown
at _B'''_, Fig. 101. The problem in hand is to find out by mechanical
experiments and tests the consequences of such a change. It is evident
that the angular motion of the pallet staff will be increased, and that
we shall have to open one of the banking pins to allow the engaging
tooth to escape. To trace out _all_ the consequences of this one little
change would require a considerable amount of study, and many drawings
would have to be made to illustrate the effects which would naturally
follow only one such slight change.

[Illustration: Fig. 100]

[Illustration: Fig. 101]

Suppose, for illustration, we should make such a change in the pallet
stone of the entrance pallet; we have increased the angle between the
lines _k l_ by (say) one and a half degrees; by so doing we would
increase the lock on the exit pallet to three degrees, provided we were
working on a basis of one and a half degrees lock; and if we pushed back
the exit pallet so as to have the proper degree of lock (one and a half)
on it, the tooth which would next engage the entrance pallet would not