greater poser was to request them to delineate a pallet and tooth when
the action of escaping was one-half or one-third performed; and it is
easy to understand that only by such studies the master workman can
thoroughly comprehend the complications involved in the club-tooth lever
escapement.


AN APT ILLUSTRATION.

As an illustration: Two draughtsmen, employed by two competing watch
factories, each designs a club-tooth escapement. We will further suppose
the trains and mainspring power used by each concern to be precisely
alike. But in practice the escapement of the watches made by one factory
would "set," that is, if you stopped the balance dead still, with the
pin in the fork, the watch would not start of itself; while the
escapement designed by the other draughtsman would not "set"--stop the
balance dead as often as you choose, the watch would start of itself.
Yet even to experienced workmen the escape wheels and pallets _looked_
exactly alike. Of course, there was a difference, and still none of the
text-books make mention of it.

For the present we will go on with delineating our exit pallet. The
preliminaries are the same as with former drawings, the instructions for
which we need not repeat. Previous to drawing the exit pallet, let us
reason on the matter. The point _r_ in Fig. 23 is located at the
intersection of pitch circle _a_ and the radial line _A c_; and this
will also be the point at which the tooth _C_ will engage the locking
face of the exit pallet.

This point likewise represents the advance angle of the engaging tooth.