Apparatus for Calculating Differences in Height Above Sea-level from Barometer Readings.

摘要

136,179. Appleyard, R. Nov. 1, 1916. Slide-rules. - Consists in apparatus for determining the correct height of one station above another, and comprising mainly a height scale, a barometric measure scale, and means for referring to a datum point on the height scale the difference between the two readings on the pressure scale. As shown, the pressure scale is a logarithmic spiral 1 used in conjunction with radial arms 2, 3 graduated in pressures, which are set on the spiral at the two pressure readings respectively, and then moved together until one arm is on the datum point of a height scale 4, whereupon the reading of the other arm gives the desired height. Instead of a logarithmic spiral 1, a pressure scale 5 projected from it may be provided, in which case the radial arms may be dispensed with. Additional scales such as 6 may be provided for correcting for temperature and lag. This appara. tus may be combined with the dial of an aneroid. One of the Provisional Specifications also mentions the use of straight scales instead of a circular one.