Altimeter, Air Section US Signal Corps, 15,000FT, WWI B-52 the difference between the totals

the difference between the totals is the difference in density of the two fuel types

as evidenced by a clear window that is visible when looking in from behind

published by the Technical Air Intelligence Center of the US Navy

which altered the angle of the projected light) to transmit Morse code

Here is a Mach Speed Indicator

Altimeter, Air Section US Signal Corps, 15,000FT, WWI B-52 the difference between the totalsThis is an Altimeter used in military aircraft of the Aviation Section, US Signal Corps, which existed from 1914 1918 and was the WWI era precursor to today's US Air Force. Made by Taylor Instruments, item # 2081 A. This altimeter crudely measured altitude from 0 15,000 ft. By loosening the small retaining lever, gripping the knurled rim of the faceplate and turning, the numerical scale rotates clockwise or counter clockwise while the pointer remains