BAROMETRICAL MEASUREMENT OF HEIGHTS. 4Q1 



Example 1. 



Suppose to be given, 



B = 333.6 Paris lines ; T = + 17°.0 Reaumur ; t = -\- 19°.0 R. ; </) = 48°. 

 B' = 289.9 Paris lines ; T' = + ]^:^ Reaumur ; t' = -\- 15° .2 R. 

 T — T' = 0°.7 t-\- t' ^-{- 34°.2 



T = -f- 8.55 

 In Table II. with B take H = 864.9 

 with B' take H' = 291.2 



H — H' = 573.7 

 H — H' 



II - ir , _„. 



_. ^- — = O-IOI 



100 



T =+8.55 



— 49 06 45 90 



100 ■ — ^^-"^ 2.87 



29 



_ (T — T') = —0.7 11 _ ir ^ 



^ ' T =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 h = 623.66 toises. 

 Gauss's Tables give 623.64 toises. 



Example 2. 



Suppose to be given, 



h = 342.68 Paris lines ; « = — 10°.38 Reaumur ; 4> = 65°. 

 b' rrr 285.47 Paris lines • i' =: — 14°.94 Reaumur ; T — T' = 0^ R. 

 t^i' ^ — 25°.32 

 r = — 6.33 

 In Table II. with b take H = 974.58 

 with b' take H' = 228.28 



H — H'= 746.30 "i^"'= •*'^-^ 



TT XT' t = — 6J3 



-~ — T = —47.24 44.78 



100 2.24 



22 



U= 699.06 «~"'.J47^24 



In Table HI., with u and t, take C = + 1.8 ^°*^ 



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



/t = 699.66 



Gauss's Tables give h = 699.72 toises. 



61 



