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 1 are given in units of the 

 = fifth decimal, we have, 



v -j- c -|~ c' = log h in toises, 



v + c + c 1 + 0.28982 = log h in metres, 



v + c + c' + 0.80584 = log h in English feet. 





Example 1. 



o 



L. station B = 329.013 Paris lines ; T = +15.88 R. ; t = + 15.96 R. ; $ = 45 32. 

 U. station B' = 268.215 Paris lines ; T' = + 8.40 R. ; t = + 7.92 R. 



t + V = 23.88 R. 



log B = 2.51722 10 x 15.88 = 2.51563 



log B' = 2.42848 10 X 8.4 = 2.42764 



u = 0.08799 



log u = 8.94443 . 



A = 3.99982 



v = 2.94425 

 c = 0.00002 

 c' = + 0.00012 



log h = 2.94435 



h = 879.74 toises. 



Example 2. 



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

 U. station B' = 600.95 millimetres ; T' = t' = 21.3 Cent. =' 17.04JR. 



t + t 1 = 37.28 R. 



log B = 9.88261 10 x 20.24 = 9.88059 

 log B ; = 9.77884 10 x 17.04 = 9.77714 



11 = 0.10345 



logti = 9.01473 



A= 4.01337 



v = 3.02810 

 c = + 0.00084 

 c' = + 0.00014 



log h = 3.02908 for toises. 

 0.28982 



log h = 3.31890 for metres, 

 log h = 3.02908 for toises. 

 0.30584 



log h = 3.83492 for English feet. 

 h = 1069.3 toises = 2084.0 metres = 6837.9 English feet. 



D 57 



