Table 1 77. 



DETERMINATION OF HEIGHTS BY THE BAROMETER. 



Formula of Babinet : Z =. C l^-S- ^ 



B^ + B 



C (in feet) = 52494 ft -f ^^ * | English measures. 



L 900 J 



C (in metres) = 16000 fi + il£<L±I}"| 



L- 1000 J 



mctnc measures. 



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

 Bq, B .= barometric readings at the lower and upper stations respectively, corrected for all 



sources of instrumental error. 

 <o, < ^ air temperatures at the lower and upper stations respectively. 



Smithsonian Tables. 



169 



