SECTION V
OPERATING INSTRUCTIONS
12.
General
Essentially, the altimeter operating instructions as described in this section are limited to reading the dial
accurately and operating the sling psychrometer (wet and dry bulb thermometers). Instructions on the use of the altimeter
in measuring altitude may be found in section VI.
13.
Dial Reading
a. After opening the cover, the altimeter is ready for operation. Essentially, operation consists of reading the dial
accurately while holding the altimeter as level as possible in a horizontal position. Readings may be made immediately
after the cover is opened; however, before reading, tap the plastic window lightly with a finger or pencil. When reading,
position the eye so that the pointer and its image in the annular mirror coincide. Error is greatly reduced if the eye sights
along the pointer and if the accessory pocket magnifier is used. Since the pointer makes four revolutions to cover the
entire range, refer to the revolution indicator to determine which of the four scales to read. Use the outside scale for the
first revolution and work in toward the center of the dial for each succeeding revolution. Count the subdivisions from the
smaller figure to the larger and interpolate to the nearest 1/2 meter.
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