maximum-minimum thermometer (fig. 11-10) is a
U-shaped, mercury-filled, glass tube with two bulbs.
You determine the current temperature by the level of
the mercury in either arm of the tube. The current
temperature indicated by the thermometer shown in
figure 11-10 is approximately 95°F. The mercury level
in each side of the tube should indicate the same
temperature reading. If the readings are not the same on
both sides of the tube, replace the thermometer.
The maximum and minimum temperatures may be
determined by observing the position of the steel index
marker located in either side of the glass tube. If the
temperature increases, the mercury rises upward in the
right-hand scale, forcing the steel index marker upward,
while the mercury in the left-hand scale decreases
downward and the steel index marker remains
stationary. If the temperature decreases, the mercury in
the left-hand scale rises, forcing the steel index marker
upward, while the mercury in the right-hand scale
decreases downward and the steel index marker remains
stationary.
The maximum temperature indicated on the
thermometer illustrated is approximately 100°F. The
reference point for taking all maximum and minimum
readings is always from the bottom edge of the steel
index marker. The minimum temperature indicated is
approximately 45°F.
After recording the temperature readings on the
magazine temperature card, zero the thermometer. You
use a horseshoe-shaped magnet to zero the thermometer.
Place the magnet against the glass and draw it downward
so each steel index marker is drawn down to the level
of mercury.
MAGAZINE TEMPERATURE LOG
A Magazine Temperature Record Card (fig. 11-11)
is located in each magazine. It is posted near the
Figure 11-10.—Maximum-minimum thermometer.
Figure 11-11.—Magazine Temperature Record Card.
11-18
