Tycos
Altimeter in Display Case, Aviation Section US Signal Corps, 15,000FT, WWI
This 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.
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 stationary, to correct the altitude reading as required. See the altimeter depicted in the JN-4D Curtiss Jenny cockpit at the Yanks Museum.
The altimeter is in exceptional condition given its age. The altimeter measures 6 inches diameter and ~2.5 inches deep. The wood-framed and glass display case measures 11 x 9 x 3 inches.