am engines, for example, ought to fulfil the conditions, and
attempts have accordingly been made upon this line with results which
have proven entirely unsatisfactory.

Having thoroughly sifted the many varieties at hand, it has been finally
determined that the only means known to provide the most regular flow of
power consists in intermittently interrupting the procession of the
wheel-work, and thereby gaining a periodically uniform movement.
Whatever may be the system or kind of escapement employed, the
functioning of the mechanism is characterized by the suspension, at
regular intervals, of the rotation of the last wheel of the train and in
transmitting to a regulator, be it a balance or a pendulum, the power
sent into that wheel.

ESCAPEMENT THE MOST ESSENTIAL PART.

Of all the parts of the timepiece the escapement is then the most
essential; it is the part which assures regularity in the running of the
watch or clock, and that part of parts that endows the piece with real
value. The most perfect escapement would be that one which should
perform its duty with the least influence upon the time of oscillation
or vibration of the regulating organ. The stoppage of the train by the
escapement is brought about in different ways, which may be gathered
under three heads or categories. In the two which we shall mention
first, the stop is effected directly upon the axis of the regulator, or
against a piece which forms a part of that axis; the tooth of the escape
wheel at the moment of its disengagement remains supported upon or
against that stop.

In the first escapement invented and, indeed, in some actually employed
to-day for certain kinds of timekeepers, we notice during the locking a
retrograde movement of the escape wheel; to this kind of movement has
been given the name of _recoil escapement_. It was recognized by the
fraternity that this recoil was prejudicial to the regularity of the
running of the mechanism and, after the invention of the pendulum and
the spiral, inventive makers succeeded in replacing this sort of
escapement with one which we now call the _dead-beat escapement_. In
this latter the wheel, stopped by the axis of the regulator, remains
immovable up to the instant of its disengagement or unlocking.

In the third category have been collected all those forms of escapement
wherein the escape wheel is locked by an intermediate piece, independent
of the regulating organ. This latter performs its vibr