This is a rare pocket altimeter barometer made by the well-known scientific instruments maker Short & Mason from London for Tycos. On the dial is engraved the dealer name Adolf Frese Optical Co Los Angeles a local scientific instruments maker and seller from early 1900. The rare high altitude barometer dial goes from 30-17 inch/hg and the altimeter scale from zero to 16000 feet adjusted by a bezel. The fine calibration is made by a small screw on the back of the device. The body of the altimeter is made of gilded brass and is in excellent condition. The original case is made of leather and satin. Unfortunately, the locking system is damaged on the case.
Dimensions: 49mm diameter and 15mm height.