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BOLEY GAUGE
55
on the sliding piece by which the jaws of the instrument are
opened, is used. On exami-
nation of the instrument, it
will be seen that the divi-
sions of this short scale (the
Vernier) equal 9 divisions on
the main scale. When the
zero divisions on the main
scale and the Vernier are
together, the instrument is
at rest and is not capable of
registering a measurement.
Now, move the first division
on the Vernier in contact
with the first division on the
main scale and the instru-
ment will register o.i milli-
meter; move the second
divisions together and, 0.2
millimeter are registered ; the
third divisions giving 0.3
millimeter, the fourth divi-
sions giving 0.4, the fifth
divisions giving 0.5, and
thus continuing until i milli-
meter is registered. The
Boley gauge is valuable for
measuring instrument
blades, plugger points, drills,
burs, differences in the meas-
FiG. 59.—Boley millimeter gauge.
urement of teeth of the same
denomination in the mouth, in comparing measurements, in
restoring angles of teeth in gold-building operations, in select-
55
on the sliding piece by which the jaws of the instrument are
opened, is used. On exami-
nation of the instrument, it
will be seen that the divi-
sions of this short scale (the
Vernier) equal 9 divisions on
the main scale. When the
zero divisions on the main
scale and the Vernier are
together, the instrument is
at rest and is not capable of
registering a measurement.
Now, move the first division
on the Vernier in contact
with the first division on the
main scale and the instru-
ment will register o.i milli-
meter; move the second
divisions together and, 0.2
millimeter are registered ; the
third divisions giving 0.3
millimeter, the fourth divi-
sions giving 0.4, the fifth
divisions giving 0.5, and
thus continuing until i milli-
meter is registered. The
Boley gauge is valuable for
measuring instrument
blades, plugger points, drills,
burs, differences in the meas-
FiG. 59.—Boley millimeter gauge.
urement of teeth of the same
denomination in the mouth, in comparing measurements, in
restoring angles of teeth in gold-building operations, in select-
