this action is reversed to start the movement, the spring, in
retracting from the wheel rim, starts the wheel swinging. Soon this slide
on the case was dispensed with by fitting a curved sheet-metal rack into
a groove turned in the edge of the balance cock. Engaging this rack was a
pinion with a square hole through which the square stem could slide to
set the hands back to zero as it had from the beginning, while turning
the stem now would actuate the pinion and rack to start and stop the
movement, as the slide in the case had originally done.

Various minor changes, dictated by experience and the need for economy in
manufacture, were made in these movements. After about the first thousand
the diameter of the balance was reduced from approximately .700 to about
.530 inch. This smaller wheel was, of course, much more suitable to
vibrate at the faster speeds required on the models beating eighths and
tenths of a second. At some time between the manufacture of watches
bearing serial numbers 3135 and 3622, the formerly separate winding pawl
and spring were combined into one piece that could be entirely made in a
punch press. Another economy move was to stamp the name and patents in
place of hand engraving. For a long time hand engraving was used,
although stamping had been used from the beginning on the earlier rotary
watch.

The case was very similar to that used on the rotary. The dial, of white
enamel with snap rim fastened by a screw,[39] carried three graduated
circles, an outer circle graduated in seconds up to sixty surrounding two
smaller subsidiary dials. The top one of these smaller dials recorded
minutes elasped up to ten and the lower one recorded fractions of a
second. The same dial was used on movements indicating quarters and
eighths of seconds, all being graduated in eighths. A dial without
provision for indicating the fractions of a second on a separate small
dial may be seen in figure 17. This last has been made into a stand for
hair spring work and is shown with balance and spring just as it came
from the Auburndale factory with balance spring and wheel for a timer
still in place.

[Illustration: Figure 18.--TAG DISPLAYING DIRECTIONS FOR USE OF THE
AUBURNDALE TIMER.

(In author's collection.)]

The sweep second hand and the minute register hand are attached to
heart-shaped cams friction driven from their respective staffs. They are
reset by a bar pivoted beneath the dial and actuated by the stem th