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National Institute of Informatics - Digital Silk Road Project
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| IIIF Color HighRes |
| Scientific Results of a Journey in Central Asia, 1899-1902 : vol.2 |
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Citation Information
METHODS OF CALCULATING THE HEIGHTS ABOVE SEA LEVEL. 591
The result was as follows:
10th-30th September 1899.
Mean temperature at Lajlik 17.°3 Cels.
Mean barometric pressure at Lajlik 662 8 mm.
Mean barometric pressure at an altitude of Soo meters above sea-level in
the vertical line of Lajlik 693.3 »
This gives by means of the barometric formula as the altitude above sea-level of Lajlik 1191 meters, whereas table I by means of the altitude of Jangi-köl has given 1173 meters, thus a difference of 18 meters. But as the value 1191 was calculated only by means of observations during 2/3 of September, it is not quite reliable, and the value 1173 is preferable.
October 1899.
Mean temperature at Haradigan-kötek i o.°3 Cels.
Mean barometric pressure at Haradigan-kötek 669.7 Illnl.
Mean barometric pressure at an altitude of 800 meters above sea-level in
the vertical line of Haradigan-kötek 697.° >
From this we find by means of the barometric formula the altitude of Haradigankötek above sea-level to be 1129 meters, exactly equal to the value found from the hydrometrical data as shown in table I.
November 1899.
Mean temperature at Modschi-toghrak o.°s Cels.
Mean barometric pressure at Modschi-toghrak 680.0 mm.
Mean barometric pressure at an altitude of 800 meters above sea-level in
the vertical line of Modschi-toghrak 699.0 »
from which the altitude above sea-level of Modschi-toghrak is found to be 1020 meters, whereas table I gives 1024 meters, thus a difference of only 4 meters.
From these results we may conclude that the values of the altitudes given in table I are so nearly exact that no further correction is needed.
The calculation of the altitudes between Jangi-köl and Kara-koschun presented more difficulty. The slopes of the river in its lower course seem to be rather unequal, with currents and still water alternating. Most of Dr. Hedin's hydrometrical observations have probably been executed in parts in which the current ran swiftest, and consequently do not give the average slope of the river, but a greater slope than the true slope. In the following table I give the result of the calculation of the difference of altitude between Jangi-köl and Kum-tschapghan. In this table the lengths correspon-
ax. 2 ax, a + a2, 3 an—s, a—x + an-1, n au-2, n
ding to the slopes s„ s , ... s„.„ s„ are 2 , 2 , • • • 2
which, when each slope is multiplied by its corresponding length gives a difference of altitude identical with that obtained by the above method of calculation.
Hedin, Journey in Central Asia. H. 75
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