Dorjiling.—Humidity 0.950 Calcutta 0.658
,, Weight of vapour 4.74 gr. ,, 8.55 gr.
NOVEMBER AND DECEMBER DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 4 The Dale,* 6952 ft. 6 a.m. 45.6 41.4 4.2 .277 8 Nov. & Dec. … 2 p.m. 60.0 48.3 11.7 .355 6 1848 … 6 p.m. 50.6 44.7 5.9 .311 9 December, … 2 p.m. 49.7 41.7 8.0 .280 19 1848 … 6 p.m. 44.0 40.5 3.5 .269 ——————————————————————————————————- 46 … … Mean 49.9 43.3 6.7 .298 ——————————————————————————————————-
CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 4 The Dale,* 6952 ft. 6 a.m. 67.9 64.7 3.2 .610 8 Nov. & Dec. … 2 p.m. 83.3 65.2 18.1 .621 6 1848 … 6 p.m. 77.3 63.1 14.2 .579 9 December, … 2 p.m. 79.3 59.0 20.3 .505 19 1848 … 6 p.m. 75.8 62.6 13.2 .569 ——————————————————————————————————- 46 … … Mean 76.7 62.9 13.8 .577 ——————————————————————————————————-
Dorjiling.—Humidity 0.798 Calcutta 0.640
,, Weight of vapour 3.40 gr. ,, 6.27 gr.
Comparison of Dorjiling and Calutta.
HUMIDITY
No. of Diff. Obs. Month Dorjiling Calcutta Dorjiling ————————————————————————————- 102 January -.795 .571 +.224 97 February .828 .590 +.238 40 March .940 -.438 +.502 23 April .684 .523 +.161 48 May .926 .698 +.228 40 June .895 .800 +.095 176 July .929 .800 +.129 167 August +.955 +.818 +.136 185 September .932 .760 +.172 74 October .950 .658 +.292 46 Nov. and Dec. .798 .640 +.158 ————————————————————————————— 998 Mean 0.876 0.663 +.212
WEIGHT OF VAPOUR IN CUBIC FOOT OF AIR
No. of Diff. Obs. Month Dorjiling Calcutta Calcutta ———————————————————————————— 102 January -2.68 -4.80 +2.12 97 February 2.75 5.40 +2.65 40 March 3.42 5.72 +2.30 23 April 3.98 7.65 +3.67 48 May 5.22 9.90 +4.62 40 June 5.39 10.17 +4.78 176 July 6.06 10.05 +3.99 167 August +6.25 +10.35 +4.10 185 September 5.72 9.88 +4.16 74 October 4.74 8.55 +3.81 46 Nov. and Dec. 3.40 6.27 +2.87 ———————————————————————————— 998 Mean 4.51 8.07 +3.55
It is hence evident, from nearly 1,000 comparative observations, that the atmosphere is relatively more humid at Dorjiling than at Calcutta, throughout the year. As the southerly current, to which alone is due all the moisture of Sikkim, traverses 200 miles of land, and discharges from sixty to eighty inches of rain before arriving at Dorjiling, it follows that the whole atmospheric column is relatively drier over the Himalaya than over Calcutta; that the absolute amount of vapour, in short, is less than it would otherwise be at the elevation of Dorjiling, though the relative humidity is so great. A glance at the table at the end of this section appears to confirm this; for it is there shown that, at the base of the Himalaya, at an elevation of only 250 feet higher than Calcutta, the absolute amount of vapour is less, and of relative humidity greater, than at Calcutta.