of
delineating a detached lever escapement, is not as conspicuous here as
it is where the pallets are drawn with equidistant locking faces; that
is, the inner angle of the entrance pallet (shown at _s_) does not have
to be carried down on the arc _d'_ as far to insure a continuous pallet
action of ten degrees, as with the pallets with equidistant locking
faces. Still, even here we have carried the angle _s_ down about half a
degree on the arc _d'_, to secure a safe lock on the exit pallet.

THE AMOUNT OF LOCK.

If we study the large drawing, where we delineate the escape wheel ten
inches in diameter, it will readily be seen that although we claim one
and a half degrees lock, we really have only about one degree, inasmuch
as the curve of the peripheral line _m_ diverges from the line _B f_,
and, as a consequence, the absolute lock of the tooth _C_ on the locking
face of the entrance pallet _E_ is but about one degree. Under these
conditions, if we did not extend the outer angle of the exit pallet at
_t_ down to the peripheral line _m_, we would scarcely secure one-half a
degree of lock. This is true of both pallets. We must carry the pallet
angles at _r s n t_ down on the circles _c'' d'_ if we would secure the
lock and impulse we claim; that is, one and a half degrees lock and
eight and a half degrees impulse.

Now, while the writer is willing to admit that a one-degree lock in a
sound, well-made escapement is ample, still he is not willing to allow
of a looseness of drawing to incorporate to the extent of one degree in
any mechanical matter demanding such extreme accuracy as the parts of a
watch. It has been claimed that such defects can, to a great extent, be
remedied by setting the escapement closer; that is, by bringing the
centers of the pallet staff and escape wheel nearer together. We hold
that such a course is not mechanical and, further, that there is not the
slightest necessity for such a policy.

ADVANTAGE OF MAKING LARGE DRAWINGS.

By making the drawings large, as we have already suggested and insisted
upon, we can secure an accuracy closely approximating perfection. As,
for instance, if we wish to get a lock of one and a half degrees on the
locking face of the entrance pallet _E_, we measure down on the arc
_c''_ from its intersection with the peripheral line _m_ one and a half
degrees, and establish the point _r_ and thus locate the outer angle of
the entrance pallet _E_, so there will really be