338 
LIEUT.-COLONEL SYKES’S DISCUSSION OF METEOROLOGICAL 
this is reversed ; considerable discrepancies occur in the results, and the tension of 
vapour is much higher (with one exception) and the per-centage of moisture much 
greater by Daniell’s hygrometer than by the wet bulb, the dew-point by the two in- 
struments differing from 3° to 5°. On the 1st of February, in the morning, the two in- 
struments differ ten per cent, in the amount of moisture in the atmosphere. In the 
afternoon they differ seven per cent., in both instances Daniell’s hygrometer giving 
the greatest amount. On August the 2nd and September the 1st, in the afternoon, the 
instruments differ above six per cent., but at this period of the year the wet bulb gives 
the greatest amount of moisture in the atmosphere and Daniell’s hygrometer the 
least. The greatest depression of the dew-point in the above observations was 22°'4 
on the 1st of May at 3^ 12™ p.m. In a former paper in the Philosophical Transactions 
I mentioned a depression of 40°, from 67° to 27°, on the 13th of March 1828 at sun- 
rise in the Hill Fort of Loghur, and of 61° on the 16th of February 1828 at 4 p.m. at 
Downde near Pairgaum on the Beema river. 
I have put into juxtaposition with this table a comparison of the results of hourly 
observations at Dodabetta of the wet bulb, with the two regular observations made 
on the same day. In November the simultaneous dew-points by the two processes 
are 36°T and 42°T5 ; in January 30°-7 and 33°'2 ; in March 43°'3 and 39°'6, and in 
April 42°‘2 and 40°‘95. Whether therefore there be 59 ^ or 69 per cent, of moisture 
in the atmosphere in November; 71 or 61^ per cent, in March ; or 73° or 78^ per 
cent, in April, nothing short of continued hourly observations, like those at Madras 
and Bombay, will enable the meteorologist to determine. 
Dodabetta. — Simultaneous observations, 8640 feet, on the 21st and 22nd of each 
month. 
Depression of the wet bulb by 
Hourly 
Twice a day, 
Dew-point by 
Dew-point by 
observations. 
ditto. 
hourly. 
twice a day. 
January 
9*2 
9-4 
30-7 
33-2 
February 
1-4 
0*9 
49-7 
50-3 
March 
5-7 
7-7 
43-3 
39-6 
April 
5-2 
4-2 
42*2 
40-95 
May 
1-8 
1-33 
54-2 
55-8 
June 
0-5 
0-2 
51-2 
51-75 
July 
0-8 
0-23 
53-15 
53-75 
August 
0-5 
0-37 
54-35 
55-43 
September 
0-4 
0-6 
52-95 
53-1 
October 
0-7 
0-4 
53-1 
52-9 
November 
7-8 
6-1 
36-1 
42-15 
December 
0-7 
0-95 
50-65 
50-65 
Any such high per-centage of moisture however was not the case on the plains 
of the Deccan, where the dew-point was determined by Daniell’s hygrometer. 
