Section II. DESCRIPTION AND DATA
Description
sights in conjunction with a mirror in the
a. General. U n m o u n t e d m a g n e t i c c o m -
cover for sighting and reading the angles.
pass M2 (figs. 1 and 2) is a multiple
pur-
The instrument has an azimuth scale ad-
pose instrument applicable to obtaining
juster for orienting the azimuth scale to
clinometer,
angle
of
site,
and
azimuth
the local magnetic declination, so that
readings. The body of the compass is
grid or Y azimuths may be read direct.
dustproof and moisture proof, and is made
b. Angle of Sight Mechanism and Re-
of nonmagnetic material except for the
lated Parts. Rotation of the level
lever
magnetic
needle
and
its
pivot.
When
the
(fig. 6) causes tie elevation level and
cover is closed, the magnetic needle is
elevation scale index to rotate as a unit.
automatically lifted from its pivot to pro-
The index clamps against the bottom piece
tect
the
pivot
point
and
jewel
bearing.
to prevent the mechanism
from moving
The jewel bearing is agate. The compass
unless actuated by the level
lever.
is provided with an angle of site scale and
c. Magnetic Needle and Lifting Mech-
an azimuth scale. The azimuth scale may
anism.
The magnetic needle provides a
be rotated approximately 1,800 mils. The
magnetic north direction for orienting pur-
compass is equipped with circular and
poses.
The
needle
is
delicately
bahmced
tubular levels. In place of a telescope,
and jewel mounted, on a pivot, to rotate
the compass employs front and rear leaf
freely. The magnetic needle reading is
Figure 1. Compass M2 and carrying case M19.
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