United States. Army. Signal Corps · Washington · leaf 99
000 feet of height. C. Index errors: The scale may not indicate the true distance from the surface of the mercury in the cistern. D. Scale errors: The graduations of the scale may not be the right distance apart. These two errors “Cr and “D?’ are best found by having the instrument tested against a… … amount varying with the temperature and height of the barometer^ This can easily be tested by tilting the barometer gently until the mercury reaches the top of the tube. If it hits the top with a sharp click the vacuum may be considered good. Aneroids and barographs. — The mercury barometer is the…
Aeronautics, Military
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
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