Hypsothermometer

A hypsothermometer ( Greek ; also thermohypsometer , barothermometer , thermobarometer ) is a device for barometric altitude measurement developed by Daniel Gabriel Fahrenheit in 1724 .

The main component of the device is a thermometer that only shows temperatures between 80 and 101 ° C , but is divided into 1 / 1,000 degrees. Thus, thousandths of a degree can still be read with some certainty.

If one determines the temperature of water vapor at any place with this instrument , which is formed by boiling water in an open vessel, one obtains the air pressure prevailing at the time of observation , since the boiling temperature depends on the air pressure. For this purpose, you add a suitably constructed boiling vessel to the boiling thermometer, both together then form the hypsothermometer.

The following table may illustrate the relationship between the boiling temperature and the barometer reading:

Siedetemperatur   Barometerstand   Näherungsweise Höhe des Ortes ü. NN
 82                 384,4            5.431 m
 84                 416,3            4.797 m
 86                 450,3            4.170 m
 88                 486,6            3.551 m
 90                 525,4            2.940 m
 92                 566,7            2.337 m
 94                 610,7            1.742 m
 96                 657,4            1.133 m
 98                 707,2              573 m
100                 760,0                0 m

Boiling temperature in ° C, barometer reading in mm Hg