Signedbelow barometric scale: CASELLA / LONDON
Inscribedon side: SCHOOL OF GEOGRAPHY HARVARD UNIVERSITY;
on thermometer scale: ABSOLUTE, and FAHR;
above barometric scale: 3289 / H.R.
FunctionA device for measuring atmospheric pressure. The mercury level in the cistern can be adjusted by the screw, allowing for the emptying of the cistern for transportation. The added precison lens allows for more accurate adjustment of the mercury level. A reading is then is taken on the scale, at the the point to which the mercury rises due to the balancing of its weight with the pressure of the surrounding air. The sliding vernier, adjustable by the center screw allows for more precise measurement of values which are between those marked on the main scale.
The small hoop on top would have been used to hang the barometer from a tripod or from a wall mounting.
The thermometer would have been used to correct the readings for temperatures that varied from the standard.
Historical AttributesOwned by Alexander Hamilton Rice, founder of the Institute of Geographical Exploration, Harvard University. Used by the Harvard School of Geography.
ProvenanceBought from the Geography Building in 1959.