BAROMETRICAL MEASUREMENT OF HEIGHTS. 



In Table III., for A, with the argument v, take c', which, in this case, is always 

 positive ; then, remembering that the values of c and c' are given in units of the 

 fifth decimal, we have, 



V -\- c -\- c' = log h in toises, 



w -f c 4- C + 0.28982 = log h in metres, 



D -f c 4- C 4- 0.80584 = log h in English feet. 



Example 1. 



L. station B = 329.013 Paris lines ; T = -f 15.88 R.; / = + 15.96 R.; (6=: 45 32. 

 U. station B' = 268.215 Paris lines ; T' = 4" 8.40 R. -, t = -{- 7.92 R. 



t-{-t'= 23.88 R. 

 log B = 2.51722 — 10 X 15.88 = 2.51563 

 log B' = 2.42848 — 10 x 8.4 = 2.42764 



Example 2. 



L. station B = 763.15 millimetres ; T = t = 25.3 Cent. = 20.24 R. ; <^ = 21. 

 U. station B' — 600.95 millimetres ; T' = i' = 21.3 Cent. — 17.04 R. 



t-{-t'=^ 37.28 R^ 



log B = 9.88261 — 10 X 20.24 = 

 log B' = 9.77884 — 1( 



log h = 3.83492 for English feet. 

 1069.3 toises = 2084.0 metres =^ 6837.9 English feet. 



57 



