'The Transactions of the Bombay Geographical Society. From January 1863 to December 1864. (Edited by the Secretary.) Volume XVII.' [‎226] (399/524)

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Art. XIII- —On a Method of Calculating Altitudes from Barortiet-
ricnl Observations without the use of Logarithms —By
J, Burgess, Esq., F.E-I.S.
[Read before the Society, April 21st, IS64.]
In the Philosophical Magazine for January 1863, I gave an investiga
tion of a method of measuring heights by means of the temperature at
which water boils; whilst preparing it my attention was also directed to
the Barometrical measurement of altitudes, and the simplification of the 1
formulae of computation. Want of leisure has, till now, prevented my
putting my results on paper.
2 . In a paper on Hypsometrical Measurements in the Journal of
the Asiatic Society of Bengal for 1858, I have shown that if we neglect
the terms dependent on the latitude of the stations and the moisture in
the air, Bessel’s formula for the difference of elevation in terms of the
atmospheric pressures and temperatures, when the best determinations
of the physical constants are employed, becomes for English measures—
V —A = 60369-15 X x (log % ~ log &) ....(1)
where T — half the sum of the temperatures t and t f at the two stations
reckoned from the freezing point, or ^ (t t' — 64°) on Fahrenheit’s
scale;
a — ^‘^^2()39, the expansion of air for 1 ° Fahr. as deter
mined by Regnault;
B and B' are the heights of the Barometer at the lower and upper
stations respectively reduced to the same temperature ;
And h 1 — h is the difference of altitude of the stations.
3, Now the formula ( 1 ) maybe written without appreciable
B
I i m cr
975*
enui
60369-15 -h * +<
.397-37
64\ ,
TSv) ! °S
Or 60521-07 (l + i±|=| 4 ) log f,