1825.] 



Barometrical Measurement of Heights, 



rV77 



Table I.^ — Correction for Moisture. 



Rule. — Divide the degrees affixed to the dew point by the 

 observed pressure in inches. 



Table II. — Value in Feet of 1° of Difference of the attached 

 Thermometers at different Temperatures of the Air. 



Sum of detached Thermometers. 



4°F 2-18 feet. 



14 ... 2-21 



24 2-24 



34 ........./.. 2-26 



44 2-29 



54 2-31 



'64 2-34 



74 2-37 



84 2-39 jn-f.r 



94 2-42 



104 -^ 2-44 



114 2-47 



124 2-50 



134 2-52 



144 2-55 



154 2-57 



164 2-60 



174 2-63 



184 2-65 



194 2-68 



Rule. — LIultiply the feet in the second column by the differ- . 

 ence of the attached thermometers, and deduct the product, 

 when the temperature of the upper barometer is inferior to the 

 other, from the difference of level, or altitude. 



Neiv Series, vol. x. .n 



