BAROMETRICAL MEASUREMENT OF HEIGHTS. 



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



Height of the Balloon of Gay-Lussac. 

 The observation gave : — 



Balloon h' = 328.80 

 Paris h =765.68 



T' = — 9.5 

 T = + 30.8 



t' = — 9.5 

 t = -f 30.8 



T — T' = 4- 40.3 {t -^t') = -\- 21.3 et 2 (« -f- 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 =z 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 4- a) = 3.8247629 



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

 Log. COS. 2 L = 97° 40' = — 9.1251872 



Log. constant = 0.0028371 = -f- 7.4528746 



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



Log. ( (0.0028371. Cos. 2 L) X (A + a) ) = — 0.4028247 



D 



Altitude of balloon = 7035.44 by the fbrmula of Laplace. 



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