Table 140 



189 



DETERMINATION OF HEIGHTS BY THE BAROMETER 



Formula of Babinet : Z 



y _ r B„ 



B + B 



C (in feet) = 52494 1 + -2-i — * English measures. 

 L goo -I 



C (in meters) = 16000 1 + ' ( " ~*~ ' metric measures. 

 L 1000 J 



In which Z = difference of height of two stations in feet or meters. 



B , B — barometric readings at the lower and upper stations respectively, corrected for all 



sources of instrumental error. 



/„, t = air temperatures at the lower and upper stations respectively. 



Values ol C 



Values only approximate. Not good for great altitudes. A more accurate formula with 

 corresponding tables may be found in Smithsonian Meteorological Tables. 



Smithsonian Tables. 



