OBSERVATIONS TAKEN IN INDIA. 
339 
The natives of the Deccan divide the year into three seasons — the Hewalla (cold), 
Oonalla (hot), and Pawsalla (wet) seasons ; the per-centage of vapour was in the 
Cold months, Nov., Decern., Jan., Feb 46^ percent, of moisture. 
Hot months, March, Apiil and May 42^ per cent, of moisture. 
Wet or monsoon months, June, July, Aug., Sept., Oct. . . 77‘4 per cent, of moisture. 
But another uncertainty is the numerical value to be given to the wet bulb read- 
ings, whether by Apjohn’s formula or by the means of factors, which Mr. Glaisher 
of the Royal Observatory has adopted from a comparison of observations between 
the wet bulb and Daniell’s hygrometer. Dr. Murray, in charge of the Sanatarium 
at Mahabuleshwur, at 4500 feet, observed with the wet bulb for nine years, and has 
given the mean monthly depression of the wet bulb for that period in the Journal of 
the Physical Society of Bombay. He does not give any details of the character of his 
instruments, or with what precautions he used them, and as from 250 to 300 inches 
of rain fall at Mahabuleshwur in the S.W. monsoon months, it might have been ex- 
pected that the air would have been much nearer to a state of saturation in those 
months than appears to be the case at Dodabetta in the same months, in which only 
29 to 30 inches of rain fall. Subjecting these observations to the two methods, it is 
seen that the results go very well together with small depressions of the wet bulb 
and at temperatures ranging from 65° to 7^°, but with depressions above 10° they 
immediately diverge, and the divergence would increase with greater depressions 
and at lower temperatures of the air. 
Mahabuleshwur. — Nine years’ Means of the Wet Bulb. 
Dry. 
Depression. 
Dew-point by 
Glaisher. 
Dew-point by 
Apjohn. 
Tension by 
Glaisher. 
Tension by 
Apjohn. 
Per-centage 
moisture by 
Glaisher. 
Per-centage 
moisture by 
Apjohn. 
January 
69-2 
9-8 
54-5 
53-35 
-435 
-418 
61-4 
59-0 
February 
69-6 
13-0 
50-1 
47-4 
-376 
-341 
32-3 
47-5 
March 
75-3 
15-7 
51-75 
49-35 
-396 
-365 
45-9 
42-3 
April 
78*1 
15*4 
55-0 
53-8 
-442 
-424 
46-9 
44-9 
May 
76*4 
9-5 
62-15 
62-4 
-562 
-566 
62-9 
63-3 
June 
70-7 
2-6 
66-8 
67-0 
-655 
-658 
88-1 
88-5 
July 
68-8 
1-8 
66-1 
66-2 
-640 
-641 
91-5 
91-6 
August 
67-4 
1-7 
64-68 
64-95 
-611 
-615 
91-4 
92-0 
September 
67-9 
2*7 
63-58 
63-95 
-589 
-596 
86-7 
87-7 
October 
68-3 
6-4 
57-96 
58-25 
-489 
-493 
71-4 
71-9 
November 
67-3 
7-7 
54-98 
54-95 
-442 
-442 
66-4 
66-4 
December 
66-9 
7-8 
54-42 
54-35 
-434 
-432 
66-0 
65-7 
Fifteen years ... 
70-4 
7*84 
58-64 
58-25 
-500 
•493 
67-9 
66-9 
Bearing therefore these discrepancies in mind, it may be justifiable to generalize 
so far only as to assert that two or three (or even four) observations with any meteorolo- 
gical instrument within the twenty-four hours, even under favourable circumstances, 
can do little more than give approximations to the truth ; and that hourly observa- 
tions, extending through four or five years at least, can alone satisfy the scientific 
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