ents when the detent is broken, and the fact that the spring
detent could not be adjusted to position. We shall have occasion to
speak of position adjustments as relate to the chronometer escapement
later on.

ADVANTAGES OF THE CHRONOMETER.

We will proceed now to consider briefly the advantages the detent
escapement has over all others. It was soon discovered in constructing
portable timepieces, that to obtain the best results the vibrations of
the balance should be as free as possible from any control or influence
except at such times as it received the necessary impulse to maintain
the vibrations at a constant arc. This want undoubtedly led to the
invention of the detent escapement. The early escapements were all
frictional escapements, i.e., the balance staff was never free from
the influence of the train. The verge escapement, which was undoubtedly
the first employed, was constantly in contact with the escape wheel, and
was what is known as a "recoiling beat," that is, the contact of the
pallets actually caused the escape wheel to recoil or turn back. Such
escapements were too much influenced by the train, and any increase in
power caused the timepiece to gain. The first attempt to correct this
imperfection led to the invention and introduction of the fusee, which
enabled the watchmaker to obtain from a coiled spring nearly equal power
during the entire period of action. The next step in advance was the
"dead-beat escapement," which included the cylinder and duplex. In these
frictional escapements the balance staff locked the train while the
balance performed its arc of vibration.

FRICTIONAL ESCAPEMENTS IN HIGH FAVOR.

These frictional escapements held favor with many eminent watchmakers
even after the introduction of the detached escapements. It is no more
than natural we should inquire, why? The idea with the advocates of the
frictional rest escapements was, the friction of the tooth acted as a
_corrective_, and led no doubt to the introduction of going-barrel
watches. To illustrate, suppose in a cylinder watch we increase the
motive power, such increase of power would not, as in the verge
escapement, increase the rapidity of the vibrations; it might, in fact,
cause the timepiece to run slower from the increased friction of the
escape-wheel tooth on the cylinder; also, in the duplex escapement the
friction of the locking tooth on the staff retards the vibrations.

Dr. Hooke, the inventor of the balance sp