BAROMETRICAL MEASUREMENT OF HEIGHTS. 



351 



Example of Calculation by the complete Formula of Laplace and by the Tables 



Height of the Balloon of Gay-Lussac. 

 The observation gave : 



mm. 



Balloon h' = 328.80 

 Paris h = 765.68 



T' = 9.5 V = 9.5 

 T = + 30.8 t = + 30.8 



T T' = + 40.3 (t + t') = + 21.3 et2 (t + t') = 42 .6 

 With these data the formula of Laplace gives the following calculation : 

 Log. h'. = 328.80 = 2.5169318 



Log. (T T') = + 40.3 = 1.6053050 



Log. dilat. coefficient = 0.0001614 == 6.2079035 



Milli. 



Corr. a = + 2.14 log. = 0.3301403 



h' = 328.80 



H = 330.94 log. = 2.5197480 



log. h = 765.68 = 2.8840473 



(Log. h Log. H) = Difference of Log. 



Log. of (Log. h log. H) 

 Log. general coefficient = 18336 = 



= 0.3642993 



9.5614583 

 4.2633046 



Log. ( (4) 18336 ) = (A + a) = 3.8247629 



Corresponding number = 6679.79 = (A -(- a) 

 Log. cos. 2 L = 97 40' = 9.1251872 



Log. constant = 0.0028371 = + 7.4528746 



Log. (A + a) = 6679.79. = + 3.8247629 



Log. ( (0.0028371. Cos. 2 L) X (A -f a) ) = 0.4028247 



Milli. 



Corresponding number = 2.53 

 6679.79 



= + 



25.03 



+ 8) = 6986.74 

 Altitude barom. Paris = 48.70 



Log. = + 1.3984372 



Altitude of balloon = 7035.44 by the formula of Laplace. 

 D 11 



