BAROMETRICAL MEASUREMENT OF HEIGHTS. 



Example 1. 



Suppose to be given, 



B = 333.6 Paris lines ; T = + 17°.0 Reaumur ; < = + 19°.0 R. ; </> = 48= 

 B' = 289.9 Paris lines ; T' == -f 16°.3 Reaumur ; r = -j" 15°.2 R. 

 T — T' = 0°.7 t-{- t' ==:-\- 34°.2 



r = 4- 8.55 



In Table II. with B take H = 864.9 

 with B' take H' r= 291.2 



H — H' = 573.7 " - -^ = 5.'37 



H — H' 



u— 21' 



■ 100 



T =+8.55 



100 • - 49-06 fg 



29 



_(T_T')=-0.7 H-ir — T 



-j^^-. =49.06 



u = 622.06 



In Table III., with u and r, take C = +1.8 

 In Table IV., with u and </>, take C ^ —0.2 

 In Table V., with T — T' and r take C" = 0.0 



Difference of elevation, or /{ = 623.66 toises. 



Gauss's Tables give 623.64 toises. 



Example 2. 



Suppose to be given, 



b = 342.68 Paris lines ■ t = — 10°.38 Reaumur ; (^ = 65". 

 b' = 285.47 Paris lines ; /' =r — 14°.94 Reaumur ; T — T' = 0°. R. 

 i 4- i' = — 25°.32 

 T = — 6.33 

 In Table II. with b take H = 974.58 

 " with b' take H' = 228.28 



H — H'= 746.30 "i^"'= ^*63 



TT TT' T = 6 .33 



^ T = 47.24 44778 



100 2.24 

 _ 22 



u= 699.06 5-n\J^^ 



In Table III., with u and t, take C = + 1.8 ^"^ 



In Table IV., with u and <^, take C' = — 1.2 



h = 699.66 



Gauss's Tables give h = 699.72 toises. 



63 



