1923%20Memoir%20on%20Maps%20of%20Chinese%20Turkistan%20by%20Stein%20s

APPENDIX I)
METHOD OF REDUCTION, 1913-15 JOURNEY
Hypsometer readings, corrected for tl~ermometer scale-error, wero retlncetl to equivalent
air pressure, and these were treatoil as f111ly corrected. Mercury barometer readings
were corrected for scale-error and reduced to freezing point. Aucrord readings were treafed
as f111l.v corrected. 111 this wq each instr~~ment. yields a fully corrected pressure.
Nest from a table, based on t.he International Meteorological Formnla (1905) tl~c
heigllt above a standard pressure level, 29.93, was read off. Tl~e result was multiplied by a
factor, taking account of tile mean air temperature. By mealis of tile Indian Daily MTeatlier
Report cliart, the value of presstue at sea-level at tlic station is estimated. Its difference
from the value 29.92 ~nultiplied I?). 873 is the necessary correction to the l~eiglit in feet.
Tl~e differences between results of aneroid and mercury barometer were taken out, and applied
to succeeding aneroid readings utit,il the nest cornparisol~ occurred. Tlie same would Ilaw
been done for the hypsometer results, if it 11ad been decided to retain t,hem.
MISTAKES OF COMPUTIITION
Uy a mistake on the part of tlie computer, uncorrected aneroid heights were given ill
four cases in place of the corrected mercury heights. Places and corrections are as follows.
Place Height giren Correctioc Final height
Toghrak-bulak 27 40 + '3; 2837
B6sh-toghrak 1980 + 3.' 2012
Kum-kuduk 3150 + 95 2245
Lowaza 1890 + 1.17 2037
RECORDS AND COAIPUTATIONS
These are at Dehra Dku, in the Computing Office, Survey of India, and are available
for reference.