BAROMF.TRirAT. MF.ASdRRMKNT OF HEIGHTS. 



415 



log [log B — log B'] = 9.04215 



In Table I. argt. r + r' = + 7.08, log V = 4.27164 



In Table 11. argt. 7.4409, log V = 0.00120 



In Table III. argt. 46°, log G' = — 0.00004 



log (H' — H) = 3.31495 



H'— H= 2065.1 metres. 



TT'2 TT2 



In Table IV. :^^^ — = + 0.9 



a a ' 



h' — /i = 2066.0 



Geneva altitude h = 407.0 



St. Bernard above the level of the sea h' = 2473.0 metres. 



Example 2. 



Computing the height of Mont Blanc from the observations of Bravais and Martins, 

 on the 29th of August, 1844, taking St. Bernard (2473.0 metres) as the lower sta- 

 tion. The observation gives, 



B = 568.03 millimetres 

 T = -f 7°.6 Centigrade 

 a = 0.59 



log B = 9.75437 



log B' = 9.62766 



log B — log B' =0.12671 



log [log B — log B'] = 



In Table I. argt. — 1°.5, log V = 



In Table II. argt. 7.2921, log V = 



In Table 111. argt. 46°, log G' = — 0.00004 



log (ir — H) = 3.36847 



ir 



B' = 424.29 millimetres 



r' = — 9°.l Centig. r + r' = — 1°.5 



a' = 0.57 « -|- «' = 1.16 



log V B B' = 

 Table I. log W = 



log (a + a') == 



, (« + «') 



lOC „ 



9.10281 

 4.26483 

 0.00087 



W 



9.6910 

 6.9183 

 0.0648 



7.2921 



H = 



In Table IV, 



2336.0 metres. 

 3.6 



f 11'== 



with argument 4800 -)- — = -|- 



'\ IP 

 I with argument 2473 = — 0.9 



h' — h = 2338.7 

 St. Bernard altitude, h = 2473.0 



Mont Blanc above the sea, h' ^= 4811.7 metres. 



D 



75 



