Hypsometer, or THERMOBAROMETER

Instrument first employed by Wollaston, and used to determine the height of a station above the sea-level by observing the boiling-point of water at the station. Thus the thermometer, used instead of the barometer for measuring heights, is very delicate and may be read to hundredths of a degree Č. If approximate results only are desired, it may be a umed that the height is sensibly proportional to the difference between the observed boiling-point and 100° C., and Soret's formula may be employed; viz., h-295(100-t), in which his given in meters and t in Centigrade degrees. If more accurate results are desired, the boiling-point will give the atmospheric pre ure by reference to a table of vapor pre ures; then if x1 and x, are the heights of two stations, p, and p, the atmospheric pre ures, the difference in height will be given by the formula Hypsometer. IMG:content-0726.jpg:[blocks in formation] IMG:content-0727.jpg:[graphic] IMG:content-0728.png:[graphic] Chandler's Encyclopedia I. Used as a symbol for unity in the Roman notation. The small letter i represents in modern analysis the unit of imaginaries -1.