DOI Seite / Zitierlink:
https://doi.org/10.11588/diglit.20140#0165
DECKEASE IN THE FREE AIE.
141
and the accumulation of clouds. Also the barometrical observations at places the height
of which is defined independently of the barometer can be used for calculating (by
inverting the formula1) the temperature which must be introduced for obtaining the
correct height; this value represents at the same time the temperature in the free
aw at half the elevation above the lower station. Before our departure already I had
occasion to try this method in the Alps; also the results I obtained for India as well
as for the Himalaya were nearly the same. The daily variation is much smaller than
at the places of observation near the surface, and where the difference of height is
very great, the maximum of the day is sensibly later in the free air than at either
station; at heights of 3000 to 4000 feet above the ground the daily variation has
the chance of disappearing nearly entirely.
As an example for Indian heights I may best select two of the days passed in
April 1856, by Dr. von Liebig, on Parisnath Hill,2 4,469 feet; the first column contains
the mean of the thermometer readings at the upper and the lower stations, the second
column is the result he obtained for the free air at half the elevation by the formula
I also had used for the Alps; my view of Parisnath, Plate 19 of the Atlas, showing
the surrounding plains, allows one at the same time to compare the topographical
conditions.
Calcutta —Parisnath Observations.
April 1856.
A. Means of temperature in the shade, deduced from the observations of the ther-
mometers, 4 feet above the ground.
B. Means of temperature for the free air, at 2,230 Engl, feet above the sea, deduced
from the barometrical observations.
1 "Physical Geography," Vol. ii., pp. 409-422.
2 "Discussion of some Meteorological Observations made on Parisnath Hill," by Dr. G. von Liebig. Journ. As
Soc. Beng., 1857, pp. 1—45.—Some minor oscillations not perfectly contemporaneous with the changes of the barometer
and thermometer are eliminated already from these numbers; altogether, some of these corrections exceed ya° C.
The degrees are Centigrade in the original.
141
and the accumulation of clouds. Also the barometrical observations at places the height
of which is defined independently of the barometer can be used for calculating (by
inverting the formula1) the temperature which must be introduced for obtaining the
correct height; this value represents at the same time the temperature in the free
aw at half the elevation above the lower station. Before our departure already I had
occasion to try this method in the Alps; also the results I obtained for India as well
as for the Himalaya were nearly the same. The daily variation is much smaller than
at the places of observation near the surface, and where the difference of height is
very great, the maximum of the day is sensibly later in the free air than at either
station; at heights of 3000 to 4000 feet above the ground the daily variation has
the chance of disappearing nearly entirely.
As an example for Indian heights I may best select two of the days passed in
April 1856, by Dr. von Liebig, on Parisnath Hill,2 4,469 feet; the first column contains
the mean of the thermometer readings at the upper and the lower stations, the second
column is the result he obtained for the free air at half the elevation by the formula
I also had used for the Alps; my view of Parisnath, Plate 19 of the Atlas, showing
the surrounding plains, allows one at the same time to compare the topographical
conditions.
Calcutta —Parisnath Observations.
April 1856.
A. Means of temperature in the shade, deduced from the observations of the ther-
mometers, 4 feet above the ground.
B. Means of temperature for the free air, at 2,230 Engl, feet above the sea, deduced
from the barometrical observations.
1 "Physical Geography," Vol. ii., pp. 409-422.
2 "Discussion of some Meteorological Observations made on Parisnath Hill," by Dr. G. von Liebig. Journ. As
Soc. Beng., 1857, pp. 1—45.—Some minor oscillations not perfectly contemporaneous with the changes of the barometer
and thermometer are eliminated already from these numbers; altogether, some of these corrections exceed ya° C.
The degrees are Centigrade in the original.