"معاملات الجمعية الجغرافية في بومباي. من يناير ١٨٦٣ حتى ديسمبر ١٨٦٤. (تحرير السكرتير.) المجلد XVII." [‎٢‎٣‎٠] (٥٢٤/٤٠٣)

f230 ON A METHOD OF CALCULATING ALTITUDES
Multiply the difference by 53775 and divide by the sum of the
readings, and to the result add the correction B taken from Table
II or computed by formula (7).
To the sum of the temperatures of the air, in Fahrenheit’s scale, add
914, and multiply the result last obtained by this sum, dividing the
product by 1000 —or, striking off three figures as decimals. This gives
the height very nearly.
Opposite the latitude X in Table III is the correction per cent, to
be applied ; and in Table IL is given the correction for variation of
gravity with the altitude?
Example.
MM. Bravais and Martins on the 29th August 1814 made the fob
lowing observations for the height of Mount Blanc :—The height of the
Barometer one metre below the summit was 424-05 ram - the attached
thermometer—4°-2 C. =24 0, 44 F. and the temperature of the air — 7°6
C. = 18 0, 32 F ; the barometer of the Observatory of Geneva (407 m
= 1335 ft. above the sea level) read 729’65 mm *, the attached thermometer
1§ 0 (3 65 0, 48 F. and the temperature of the air 19°3 C 9 = 66°74F-
B
Here t—t'= 65°-48-
729 - 65mm.
_24 o - 44-=41°-04.
Constant
914
41 of I? ..
—3*00
t
66-74
18-32
999*06
10000
B corrected..
726-65
t'
424-05
Sum.
B — B'
C
53775
B 4 " B f ......
1 >715070.
X B —B'
6203
Product.
Dividing 16272*3 by J5-f JT=lU1507, the quotient is
By Table II, D for 14000 ....
Prop, part for 148
99906
1000
1000—0-94
Mbob™ 5
and p. p. for *94
Sum
.\ h' — h
14481-8 X - 99 ' Q6
1000
161325
1075
323
16272*3
14147-7
323-3
10-8
14481-8 ft.
—13*5
Tiios 7 ^ ft?