Callaghan & Co. pocket barometer/altimeter and thermometer
Callaghan & Co.
overall: 1/2 in x 6 in x 2 1/4 in
Pocket barometer/altimeter and thermometer. Barometer is calibrated in both inches of Hg (21 to 31) and in feet of altitude (0 to 10,000). In the case is a glass thermometer formed into a small circle with calibrations in both Fahrenheit and Centigrade.