The simplest form of the detached lever escapement in use is the one
known as the "ratchet-tooth lever escapement," and generally found in
English lever watches. This form of escapement gives excellent results
when well made; and we can only account for it not being in more general
use from the fact that the escape-wheel teeth are not so strong and
capable of resisting careless usage as the club-tooth escape wheel.

It will be our aim to convey broad ideas and inculcate general
principles, rather than to give specific instructions for doing "one
thing one way." The ratchet-tooth lever escapements of later dates
have almost invariably been constructed on the ten-degree
lever-and-pallet-action plan; that is, the fork and pallets were
intended to act through this arc. Some of the other specimens of this
escapement have larger arcs--some as high as twelve degrees.


PALLET-AND-FORK ACTION.

[Illustration: Fig. 5]

We illustrate at Fig. 5 what we mean by ten degrees of pallet-and-fork
action. If we draw a line through the center of the pallet staff, and
also through the center of the fork slot, as shown at _a b_, Fig. 5, and
allow the fork to vibrate five degrees each side of said lines _a b_, to
the lines _a c_ and _a c'_, the fork has what we term ten-degree pallet
action. If the fork and pallets vibrate six degrees on each side of the
line _a b_--that is, to the lines _a d_ and _a d'_--we have twelve
degrees pallet action. If we cut the arc down so the oscillation is only
four and one-quarter degrees on each side of _a b_, as indicated by the
lines _a s_ and _a s'_, we have a pallet-and-fork action of eight and