B. G. ON THE RELATIVE HUMIDITY, AND ABSOLUTE AMOUNT OF VAPOUR CONTAINED IN THE ATMOSPHERE AT DIFFERENT ELEVATIONS IN THE SIKKIM HIMALAYA. My observations for temperature and wet-bulb being for the most part desultory, taken at different dates, and under very different conditions of exposure, etc., it is obvious that those at one station are hardly, if at all, comparative with those of another, and I have therefore selected only such as were taken at the same date and hour with others taken at the Calcutta Observatory, or as can easily be reduced; which thus afford a standard (however defective in many respects) for a comparison. I need hardly remind my reader that the vapour-charged wind of Sikkim is the southerly one, which blows over Calcutta; that in its passage northwards to Sikkim in the summer months, it traverses the heated plains at the foot of the Himalaya, and ascending that range, it discharges the greater part of its moisture (120 to 140 inches annually) over the outer Himalayan ranges, at elevations of 4000 to 8000 feet. The cooling effect of the uniform covering of forest on the Sikkim ranges is particularly favourable to this deposition, but the slope of the mountains being gradual, the ascending currents are not arrested and cooled so suddenly as in the Khasia mountains, where the discharge is consequently much greater. The heating of the atmosphere, too, over the dry plains at the foot of the outer range, increases farther its capacity for the retention of vapour, and also tends to render the rain-fall less sudden and violent than on the Khasia, where the south wind blows over the cool expanse of the Jheels. It will be seen from the following observations, that in Sikkim the relative humidity of the atmosphere remains pretty constantly very high in the summer months, and at all elevations, except in the rearward valleys; and even there a humid atmosphere prevails up to 14,000 feet, everywhere within the influence of the snowy mountains. The uniformly high temperature which prevails throughout the summer, even at elevations of 17,000 and 18,000 feet, is no doubt proximately due to the evolution of heat during the condensation of these vapours. It will be seen by the pages of my journal, that continued sunshine, and the consequent heating of the soil, is almost unknown during the summer, at any elevation on the outer or southward ranges of Dorjiling: but the sunk thermometer proves that in advancing northward into the heart of the mountains and ascending, the sun’s effect is increased, the temperature of the earth becoming in summer considerably higher than that of the air. With regard to the observations themselves, they may be depended upon as comparable with those of Calcutta, the instruments having been carefully compared, and the cases of interpolation being few. The number of observations taken at each station is recorded in a separate column; where only one is thus recorded, it is not to be regarded as a single reading, but the mean, of several taken during an hour or longer period. I have rejected all solitary observations, even when accompanied by others at Calcutta; and sundry that were, for obvious reasons, likely to mislead. Where many observations were taken at one place, I have divided them into sets, corresponding to the hours at which alone the Calcutta temperature and wet-bulb thermometer are recorded, [423] in order that meteorologists may apply them to the solution of other questions relating to the distribution of heat and moisture. The Dorjiling observations, and those in the immediate neighbourhood of that station, appeared to me sufficiently numerous to render it worth while classing them in months, and keeping them in a series by themselves. The tensions of vapour are worked from the wet-bulb readings by Apjohn’s formula and tables, corrected for the height of the barometer at the time. The observations, except where otherwise noted, are taken by myself. [423] Sunrise; 9.50 a.m.; noon; 2.40 p.m.; 4 p.m., and sunset. SERIES I. Observations made at or near Dorjiling. JANUARY, 1849 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 15 15 10 8 9 The Dale, [424] Mr. Muller’s … … … 6956 … … … … 9.50 a.m. Noon 2.40 p.m. 4 p.m. Sunset 42·9 45·8 48·3 48·6 46·5 32·4 33·8 37·4 37·8 37·1 10·5 12·0 10·9 10·8 9·4 ·202 ·212 ·241 ·244 ·238 67·5 72·9 76·1 75·1 71·8 55·3 55·7 55·1 54·8 54·9 12·2 17·2 21·0 20·3 16·9 ·446 ·455 ·444 ·440 ·441 57 … … Mean 46·4 35·7 10·7 ·227 72·7 55·2 17·5 ·445 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·700 2·63 gr. 0·562 4·86 gr. [424] Observations were taken by Mr. Muller. JANUARY, 1850 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 3 6 3 5 5 5 13 4 1 Jillapahar, Mr. Hodgson’s … … … … … Saddle of road at Sinchul Pacheem 7430 … … … … … … 7412 7258 Sunrise 9.50 a.m. Noon 2.40 p.m. 4 p.m. Sunset Miscel. Do. Do. 32·8 39·5 42·4 41·9 41·1 38·7 41·9 41·1 39·8 30·1 34·7 38·0 37·8 38·5 35·6 39·9 36·4 38·7 2·7 4·8 4·4 4·1 2·6 3·1 2·0 4·7 1·1 ·186 ·219 ·246 ·244 ·250 ·226 ·263 ·233 ·252 51·5 66·9 74·1 78·3 77·4 72·4 77·9 67·7 71·6 48·5 55·1 51·7 51·4 59·5 54·7 60·1 57·2 50·5 3·0 11·8 22·4 26·9 17·9 17·7 17·8 10·5 21·1 ·354 ·444 ·395 ·391 ·514 ·438 ·525 ·476 ·379 45 … … Mean 39·9 36·6 3·3 ·235 70·9 54·3 16·6 ·435 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·890 2·75 gr. 0·580 4·86 gr. FEBRUARY, 1850 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 6 18 12 12 17 19 13 Jillapahar … … … … … The Dale [425] 7430 … … … … … 6956 Sunrise 9.50 a.m. Noon 2.40 p.m. 4 p.m. Sunset Misc. 36·9 42·9 44·8 44·8 44·0 42·4 40·8 34·7 38·6 41·3 37·4 35·6 35·8 35·1 2·2 4·3 3·5 7·4 8·4 6·6 5·7 ·219 ·251 ·276 ·241 ·226 ·228 ·222 60·0 72·8 79·8 82·4 81·1 76·3 69·9 54·2 58·8 58·7 57·9 58·1 60·7 59·8 5·8 14·0 21·1 24·5 23·0 15·6 10·1 ·431 ·503 ·501 ·487 ·492 ·536 ·518 97 … … Mean 42·4 36·9 5·4 ·238 74·6 58·3 16·3 ·495 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·828 2·75 gr. 0·590 5·40 gr. [425] Observations were taken by Mr. Muller. MARCH, 1850 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 10 8 5 8 6 3 Jillapahar … … … … Pacheem 7430 … … … … 7258 9.50 a.m. Noon 2.40 p.m. 4 p.m. Sunset Miscel. 44·2 45·5 46·4 45·5 43·1 44·8 42·7 43·0 44·0 43·4 41·5 44·6 1·5 2·5 2·4 2·1 1·6 0·2 ·290 ·293 ·303 ·297 ·278 ·310 81·6 88·2 91·3 90·1 82·9 85·0 64·1 57·0 53·2 52·0 63·7 74·8 17·5 31·2 38·1 38·1 19·2 10·2 ·602 ·472 ·416 ·399 ·590 ·848 40 … … Mean 44·9 43·2 1·7 ·295 86·5 60·8 25·7 ·555 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·940 3·42 gr. 0·438 5·72 gr. APRIL DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 3 3 1 7 2 4 3 Jillapahar, 1849 … … Dr. Campbell’s, 1850 … … … 7430 … … 6932 … … … 9.50 a.m. Noon 2.40 p.m. 9.50 a.m. Noon 4 p.m. 57·0 59·8 60·2 61·8 65·4 57·5 56·9 40·2 44·1 44·4 53·3 52·8 53·7 51·4 16·8 15·7 15·8 8·5 12·6 3·8 5·5 ·266 ·305 ·308 ·417 ·411 ·423 ·392 90·3 97·0 97·7 86·7 91·3 88·6 82·8 71·3 64·5 73·4 66·3 68·8 72·1 73·0 19·0 32·5 24·3 20·4 22·5 16·5 9·8 ·758 ·607 ·812 ·644 ·699 ·778 ·800 23 … … Mean 59·8 48·6 11·3 ·360 90·6 69·9 20·7 ·728 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·684 3·98 gr. 0·523 7·65 gr. MAY DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 3 45 Smith’s Hotel, 1848 Colinton, [426] 1849 6863 7179 Miscel. Miscel. 57·2 60·4 55·0 57·9 2·2 1·5 ·443 ·466 88·6 90·0 78·4 77·2 10·2 12·8 ·951 ·917 48 … Mean 58·8 56·5 2·4 ·455 89·3 77·8 11·5 ·934 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·926 5·22 gr. 0·698 9·90 gr. [426] Observations were taken by Mr. Muller. JUNE DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 40 Colinton, [427] 7179 Miscel. 60·9 57·6 3·3 ·483 85·5 78·4 7·1 ·952 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·895 5·39 gr. 0·800 10·17 gr. [427] Observations were taken by Mr. Muller. JULY, 1848 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 18 25 24 16 31 31 31 Jillapahar … … … The Dale, [428] … … 7430 … … … 6952 … … 9.50 a.m. Noon 2.40 p.m. 4 p.m. 6 a.m. 2 p.m. 6 p.m. 63·2 65·0 64·7 63·8 60·2 66·3 63·0 61·4 62·6 62·3 61·5 58·7 63·3 60·9 1·8 2·4 2·4 2·3 1·5 3·0 2·1 ·548 ·570 ·565 ·550 ·537 ·621 ·575 87·0 89·0 88·1 87·2 81·3 88·0 84·8 79·4 80·0 79·4 79·5 79·0 79·6 79·2 7·6 9·0 8·7 7·7 2·3 8·4 5·6 ·983 1·001 ·983 ·985 ·969 ·989 ·977 176 … … Mean 63·7 61·5 2·2 ·567 86·5 79·4 7·0 ·984 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·929 6·06 gr. 0·800 10·45 gr. [428] Observations were taken by Mr. Muller. AUGUST, 1848 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 23 21 17 13 31 31 31 Jillapahar … … … The Dale, [429] … … 7430 … … … 6952 … … 9.50 a.m. Noon 2.40 p.m. 4 p.m. 6 a.m. 2 p.m. 6 p.m. 64·2 64·7 64·7 63·9 60·5 65·3 62·8 62·4 63·3 62·8 62·5 59·5 63·6 61·8 1·8 1·4 1·9 1·4 1·0 1·7 1·0 ·567 ·584 ·574 ·568 ·551 ·628 ·591 85·8 87·2 87·4 86·5 80·8 87·2 83·7 79·1 79·2 79·3 79·5 78·8 79·2 78·7 6·7 8·0 8·1 7·0 2·0 8·0 5·0 ·973 ·976 ·979 ·984 ·962 ·976 ·959 167 … … Mean 63·7 62·3 1·5 ·580 85·5 79·1 6·4 ·973 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·995 6·25 gr. 0·818 10·35 gr. [429] Observations were taken by Mr. Muller. SEPTEMBER, 1848 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 28 23 23 21 30 30 30 Jillapahar … … … The Dale, [430] … … 7430 … … … 6952 … … 9.50 a.m. Noon 2.40 p.m. 4 p.m. 6 a.m. 2 p.m. 6 p.m. 60·8 62·4 62·4 62·0 57·4 64·9 60·8 59·3 60·3 59·6 59·6 56·2 60·8 59·0 1·5 2·1 2·8 2·4 1·2 4·1 1·8 ·511 ·528 ·516 ·516 ·495 ·573 ·543 87·0 88·5 88·1 86·9 80·9 88·8 84·7 78·4 78·1 77·4 77·1 78·3 77·4 76·6 8·6 10·4 10·7 9·8 2·6 11·4 8·1 ·952 ·943 ·922 ·914 ·948 ·923 ·899 185 … … Mean 61·5 59·3 2·3 ·526 86·4 77·6 8·8 ·929 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·932 5·72 gr. 0·760 9·88 gr. [430] Observations were taken by Mr. Muller. OCTOBER, 1848 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 6 6 6 4 8 8 17 19 Jillapahar … … Goong. Ditto The Dale, [431] … … 7430 … … 7436 7441 6952 … … Noon 2.40 p.m. 4 p.m. Misc. Misc. 6 a.m. 2 p.m. 6 p.m. 55·9 55·7 55·6 48·3 51·2 55·2 61·4 56·9 55·3 54·9 54·9 48·3 50·2 52·7 56·3 54·2 0·6 0·8 0·7 0 1·0 2·5 5·1 2·7 ·446 ·440 ·441 ·352 ·376 ·439 ·497 ·463 84·4 86·0 85·2 81·2 80·7 76·1 87·0 82·8 75·3 73·3 74·4 73·7 66·9 74·2 71·2 73·9 9·1 12·7 10·8 7·5 13·8 1·9 15·8 8·9 ·863 ·808 ·837 ·819 ·657 ·834 ·756 ·824 74 … … Mean 55·0 53·4 1·7 ·432 82·9 72·9 10·1 ·800 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·950 4·74 gr. 0·658 8·55 gr. [431] Observations were taken by Mr. Muller. NOVEMBER AND DECEMBER, 1848 DORJILING CALCUTTA No. of Obs. Place Elev. (feet) Hour Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 4 8 6 9 19 The Dale [432] Nov./Dec. … December … 6952 … … … … 6 a.m. 2 p.m. 6 p.m. 2 p.m. 6 a.m. 45·6 60·0 50·6 49·7 44·0 41·4 48·3 44·7 41·7 40·5 4·2 11·7 5·9 8·0 3·5 ·277 ·355 ·311 ·280 ·269 67·9 83·3 77·3 79·3 75·8 64·7 65·2 63·1 59·0 62·6 3·2 18·1 14·2 20·3 13·2 ·610 ·621 ·579 ·505 ·569 46 … … Mean 49·9 43·3 6·7 ·298 76·7 62·9 13·8 ·577 Dorjiling Calcutta Humidity Vapour in cubic foot of atmosphere 0·798 3·40 gr. 0·640 6·27 gr. [432] Observations were taken by Mr. Muller. Comparison of Dorjiling and Calcutta. HUMIDITY WEIGHT OF VAPOUR IN CUBIC FOOT OF AIR No. of Obs. Month Dorjiling Calcutta Diff. Dorjiling Dorjiling Calcutta Diff. Calcutta 102 97 40 23 48 40 176 167 185 74 46 January February March April May June July August September October Nov. and Dec. –·795 ·828 ·940 ·684 ·926 ·895 ·929 +·955 ·932 ·950 ·798 ·572 ·590 –·438 ·523 ·698 ·800 ·800 +·818 ·760 ·658 ·640 +·224 +·238 +·502 +·161 +·228 +·095 +·129 +·136 +·172 +·292 +·158 –2·68 2·75 3·42 3·98 5·22 5·39 6·06 +6·25 5·72 4·74 6·27 –4.80 5·40 5·72 7·65 9·90 10·17 10·05 +10·35 9·88 8·55 6·27 +2·12 +2·65 +2·30 +3·67 +4·62 +4·78 +3·99 +4·10 +4·16 +3·81 +2·87 998 Mean 0·876 0·663 +·212 4·51 8·07 +3·55 It is hence evident, from nearly 1000 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. SERIES II. Observations at various Stations and Elevations in the Himalaya of East Nepal and Sikkim. ELEVATION 735 TO 2000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 3 2 1 3 1 6 1 5 5 11 10 Katong Ghat, Teesta river Great Rungeet, at bridge Ditto Tambur river, E. Nepal Ditto Bhomsong, Teesta river Ditto Little Rungeet Pemiongchi, Great Rungeet Punkabaree Ditto Guard house (Gt. Rungeet) 735 818 818 1388 1457 1596 1596 1672 1840 1850 1850 1864 Dec. April May Nov. Nov. Dec. May Jan. Dec. March May April 60·2 82·8 77·8 60·6 64·2 58·6 68·2 51·0 54·6 70·1 73·5 73·7 55·3 63·5 60·3 57·0 59·1 52·0 66·4 50·2 53·7 55·6 68·3 63·8 4·9 19·3 17·5 3·6 5·1 6·6 1·8 0·8 0·9 14·5 5·2 9·9 ·447 ·588 ·528 ·473 ·507 ·399 ·647 ·377 ·424 ·472 ·687 ·592 73·2 95·8 91·7 73·3 77·3 71·6 82·6 58·5 73·5 79·2 83·7 92·4 56·7 61·9 78·3 62·7 63·4 57·0 77·4 58·0 66·2 62·6 77·9 67·0 16·5 33·9 13·4 10·6 13·9 14·6 5·2 0·5 7·3 16·6 5·8 25·4 ·468 ·557 ·947 ·571 ·585 ·474 ·923 ·489 ·642 ·570 ·938 ·660 48 Mean 66·3 58·8 7·5 ·512 79·4 65·8 13·6 ·652 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·717 5·57 gr. 0·663 6·88 gr. ELEVATION 2000 TO 3000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 2 8 3 3 2 8 12 8 3 Singdong Mywa Guola, E. Nepal Pemmi river, E. Nepal Tambur river, E. Nepal Blingbong (Teesta) Lingo (Teesta) Serriomsa (Teesta) Lingmo (Teesta) Ditto 2116 2132 2256 2545 2684 2782 2820 2849 2952 Dec. Nov. Nov. Nov. May May Dec. May Dec. 60·5 66·2 55·6 57·3 72·6 75·8 64·1 68·6 56·4 53·4 57·5 53·9 51·6 64·0 67·3 56·8 64·6 53·5 7·1 8·7 1·7 5·7 8·6 8·5 7·3 4·0 2·9 ·419 ·481 ·426 ·394 ·597 ·666 ·469 ·610 ·420 72·1 75·7 62·9 75·0 81·7 90·7 70·8 87·9 69·5 52·9 68·7 62·3 63·7 73·6 77·7 62·4 74·9 66·5 19·2 7·0 0·6 11·3 8·1 13·0 8·4 13·0 3·0 ·411 ·697 ·566 ·591 ·817 ·932 ·567 ·851 ·647 49 Mean 64·1 58·1 6·1 ·498 76·3 67·0 9·3 ·675 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·820 5·45 gr. 0·740 7·13 gr. ELEVATION 3000 TO 4000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 5 9 3 2 2 7 7 1 3 1 1 2 5 Kulhait river Ratong river Tambur river Chingtam Tikbotang Myong Valley Iwa river Ratong river Tukcham Pacheem village Yankoong Mikk Sunnook 3159 3171 3201 3404 3763 3782 3783 3790 3849 3855 3867 3912 3986 Jan. Jan. Nov. Nov. Dec. Oct. Dec. Jan. Nov. Jan. Dec. May Dec. 49·8 44·2 53·0 54·8 56·5 61·4 47·5 56·2 68·8 54·5 50·0 66·1 47·9 47·0 43·0 50·0 49·0 53·4 58·4 45·6 41·1 65·4 46·3 43·6 63·9 45·5 2·8 1·2 3·0 5·8 3·1 3·0 1·9 15·1 3·4 8·2 6·4 2·2 2·4 ·337 ·294 ·373 ·360 ·419 ·496 ·321 ·275 ·625 ·329 ·299 ·595 ·320 65·8 69·9 72·9 74·9 68·0 80·7 73·3 75·8 83·7 73·6 69·1 84·3 69·4 57·3 56·6 63·2 73·0 61·8 71·2 64·7 53·0 76·8 59·4 63·8 75·1 61·1 8·5 13·3 9·7 1·9 6·2 9·5 8·6 22·8 6·9 14·2 5·3 9·2 8·3 ·477 ·466 ·582 ·802 ·555 ·755 ·611 ·414 ·904 ·513 ·593 ·856 ·542 48 Mean 54·7 50·2 4·5 ·388 74·0 64·4 9·6 ·621 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·858 4·23 gr. 0·732 6·60 gr. ELEVATION 4000 TO 5000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 3 4 2 3 7 3 6 7 10 5 5 2 16 6 4 4 2 4 7 6 3 6 11 9 Yangyading Gorh Namgah Taptiatok (Tambur) Myong Valley Jummanoo Nampok Chakoong Singtam Namten Purmiokshong Rungniok Singtam Cheadam Sablakoo Bheti Temi Lingtam Khersiong Ditto Tassiding Lingcham Dikkeeling Tchonpong 4111 4128 4229 4283 4345 4362 4377 4407 4426 4483 4521 4565 4575 4653 4676 4683 4771 4805 4813 4813 4840 4870 4952 4978 Dec. May Oct. Nov. Oct. Nov. Dec. May May Dec. Nov. Jan. Oct/Nov. Dec. Dec. Nov. May May Jan. Mar. Dec. Dec. Dec. Jan. 52·0 66·4 57·2 51·3 59·1 60·4 49·6 57·8 62·4 44·7 60·5 54·7 63·8 51·4 50·1 59·0 59·8 60·4 51·0 53·6 52·0 48·5 62·0 49·4 43·6 59·0 54·1 45·8 57·8 50·0 49·1 57·6 61·7 44·3 56·5 44·3 60·1 46·6 44·9 52·3 50·1 56·6 45·2 45·5 46·6 46·1 55·3 34·7 8·4 7·4 3·1 5·5 1·3 10·4 0·5 0·2 0·7 0·4 4·0 10·4 3·7 4·8 5·2 6·7 9·7 3·8 5·8 8·1 5·4 2·4 6·7 14·7 ·300 ·506 ·429 ·323 ·487 ·374 ·362 ·483 ·553 ·307 ·466 ·307 ·525 ·332 ·314 ·405 ·374 ·467 ·316 ·320 ·333 ·327 ·447 ·219 71·1 85·5 80·8 73·3 81·7 77·4 64·1 83·9 88·6 64·8 79·2 66·5 82·5 70·2 72·9 78·3 81·2 80·0 67·0 77·1 79·7 78·5 80·8 71·0 67·2 74·2 73·7 64·8 72·9 70·2 56·3 76·2 79·0 58·3 69·5 59·7 76·7 55·0 65·7 66·1 74·1 73·8 49·8 70·5 60·8 71·8 62·0 54·7 3·9 11·3 7·1 8·5 8·8 7·2 7·8 7·7 9·6 6·5 9·7 6·8 5·8 15·2 7·2 12·2 7·1 6·2 17·2 6·6 18·9 6·7 18·8 16·3 ·663 ·834 ·819 ·614 ·797 ·731 ·462 ·889 ·969 ·495 ·715 ·517 ·901 ·442 ·632 ·639 ·834 ·820 ·370 ·738 ·538 ·771 ·559 ·439 137 Mean 55·7 50·4 5·4 ·387 76·5 66·8 9·7 ·675 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·837 4·33 gr. 0·730 7·12 gr. ELEVATION 5000 TO 6000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 4 4 2 7 5 3 4 6 8 8 7 6 8 5 6 3 8 6 3 4 6 16 2 4 3 3 3 3 2 3 3 22 21 20 21 21 Nampok Tengling Choongtam, sunrise Choongtam, 9.50 a.m. Choongtam, noon Choongtam, 2.45 p.m. Choongtam, 4 p.m. Choongtam, sunset Choongtam, 9.50 a.m. Choongtam, noon Choongtam, 2.40 p.m. Choongtam, 4 p.m. Choongtam, sunset Sulloobong Lingdam Makaroumbi Khabang Lingdam Yankutamg Namtchi Yoksun Ditto Loongtoon Sakkiazong Phadong, 8 a.m. Phadong, 9.50 a.m. Phadong, noon Phadong, 2.40 p.m. Phadong, 4 p.m. Phadong, sunset Tumloong Tumloong, 9. 50 a.m. Tumloong, noon Tumloong, 2.40 p.m. Tumloong, 4 p.m. Tumloong, sunset 5075 5257 5368 5368 5368 5368 5368 5368 5368 5368 5368 5368 5368 5277 5375 5485 5505 5554 5564 5608 5619 5619 5677 5625 5946 5946 5946 5946 5946 5946 5368 5976 5976 5976 5976 5976 May Jan. May May May May May May Aug. Aug. Aug. Aug. Aug. Nov. Dec. Nov. Dec. Dec. Dec. May Jan. Jan. Nov. Nov. Nov. Nov. Nov. Nov. Nov. Nov. Nov. Nov/Dec. Nov/Dec. Nov/Dec. Nov/Dec. Nov/Dec. 65·8 44·7 54·9 71·5 71·0 66·4 63·5 61·4 76·3 78·8 72·9 69·5 66·9 57·6 44·3 52·1 55·1 45·0 43·6 67·1 42·7 43·0 45·3 54·1 51·9 55·9 60·7 57·4 55·5 53·7 64·2 54·1 57·3 57·3 54·7 51·8 60·8 39·1 54·7 58·9 59·4 59·4 59·2 60·5 66·1 67·8 66·5 66·8 65·4 51·2 43·0 48·1 47·3 43·7 41·7 61·2 34·0 33·9 42·8 50·9 50·8 53·0 56·5 54·7 52·8 52·6 62·6 50·0 51·7 51·4 50·5 48·5 5·0 5·6 0·2 12·6 11·6 7·0 4·3 0·9 10·2 11·0 6·4 2·7 1·5 6·4 1·3 4·0 7·8 1·3 1·9 5·9 8·7 9·1 2·5 3·2 1·1 2·9 4·2 2·7 2·7 1·1 1·6 4·1 5·6 5·9 4·2 3·3 ·537 ·257 ·438 ·504 ·513 ·513 ·510 ·532 ·640 ·677 ·649 ·655 ·627 ·390 ·293 ·350 ·340 ·301 ·280 ·544 ·214 ·213 ·292 ·358 ·383 ·413 ·465 ·438 ·410 ·408 ·570 ·375 ·396 ·391 ·380 ·355 83·1 65·4 78·2 89·8 92·7 95·4 93·6 89·1 85·3 86·6 86·4 85·3 83·6 79·4 68·8 72·5 75·0 71·0 69·5 87·7 68·2 66·2 72·1 78·3 75·0 80·9 85·6 86·6 85·5 80·6 83·8 75·1 79·7 81·3 80·2 76·7 74·7 38·1 73·9 80·0 79·9 78·7 79·0 77·1 78·9 78·8 78·8 79·3 78·5 65·8 59·9 60·5 64·7 56·5 63·1 74·9 58·1 51·9 63·8 66·1 67·5 67·9 64·8 62·2 61·9 67·4 77·5 61·9 60·1 58·0 58·6 61·2 8·4 27·3 4·3 9·8 12·8 16·7 14·6 12·0 6·4 7·8 7·6 6·0 5·1 13·6 8·9 12·0 10·3 14·5 6·4 12·8 10·1 14·3 8·3 12·2 7·5 13·0 20·8 24·4 23·6 13·2 6·3 13·2 19·6 23·3 21·6 15·5 ·845 ·247 ·826 1·000 ·999 ·959 ·971 ·915 ·967 ·965 ·963 ·980 ·956 ·634 ·521 ·532 ·611 ·466 ·579 ·850 ·492 ·399 ·595 ·639 ·670 ·678 ·613 ·562 ·557 ·667 ·924 ·557 ·524 ·489 ·499 ·545 260 Mean 57·7 53·3 4·5 ·438 77·6 67·8 9·8 ·700 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·865 4·70 gr. 0·730 7·34 gr. ELEVATION 6000 TO 7000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 5 11 11 4 2 4 4 3 1 10 4 6 7 4 Runkpo Leebong Ditto Dholeep Iwa River Dengha Kulhait River Latong Doobdi Pemiongchi Keadom Hee-hill Dumpook Changachelling 6008 6021 6021 6133 6159 6368 6390 6391 6472 6584 6609 6677 6678 6828 Nov. Feb. Jan. May Dec. Aug. Dec. Oct. Jan. Jan. Aug. Jan. Jan. Jan. 57·5 47·8 47·8 60·5 41·2 66·7 41·9 54·0 46·6 40·7 63·5 40·8 40·2 50·6 54·8 43·7 43·4 59·9 40·5 64·0 41·9 53·2 36·2 35·8 60·0 34·1 31·8 31·8 2·7 4·1 4·4 0·6 0·7 2·7 0 0·8 10·4 4·9 3·5 6·7 8·4 18·8 ·440 ·300 ·297 ·520 ·269 ·597 ·283 ·416 ·231 ·228 ·523 ·215 ·198 ·198 79·5 74·9 66·9 89·4 69·6 86·1 71·3 55·5 78·7 66·3 79·7 64·0 68·5 68·3 73·4 59·7 56·2 81·4 60·2 78·8 60·9 44·1 58·0 54·4 77·5 58·0 53·8 53·6 6·1 15·2 10·7 8·0 9·4 7·3 10·4 11·4 20·7 11·9 2·2 6·0 14·7 14·8 ·810 ·517 ·460 ·046 ·527 ·962 ·539 ·305 ·490 ·434 ·925 ·489 ·426 ·423 76 Mean 50·0 45·1 4·9 ·337 72·8 62·1 10·6 ·597 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·845 3·60 gr. 0·701 6·11 gr. ELEVATION 7000 TO 8000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 1 2 8 1 1 4 8 Pemiongchi Goong Kampo-Samdong Hee-hill Ratong river Source of Balasun Goong ridge 7083 7216 7329 7289 7143 7436 7441 Jan. Nov. May/Aug. Jan. Jan. Oct. Oct. 46·2 49·0 59·1 51·3 36·5 48·3 51·2 33·5 48·5 58·2 26·4 25·3 48·3 50·2 12·7 0·5 0·9 24·9 11·2 0 1·0 ·210 ·355 ·493 ·163 ·157 ·352 ·376 76·8 79·7 83·6 72·8 60·0 81·2 80·7 51·8 69·1 77·4 56·6 52·9 73·7 66·9 25·0 10·6 6·2 16·2 7·1 7·5 13·8 ·396 ·705 ·922 ·466 ·412 ·819 ·657 35 Dorjiling Mean 48·8 41·5 7·3 ·301 76·4 64·1 12·8 ·625 From mean of above and Dorjiling Calcutta Humidity Weight of vapour 0·826 3·85 gr. 0·668 7·28 gr. ELEVATION 8000 TO 9000 FEET EAST NEPAL AND SIKKIM CALCUTTA No. of Obs. Locality Elev. Month Temp. Dew Point Diff. Tens. Temp. Dew Point Diff. Tens. 4 2 1 2 3 4 6 9 1 11 12 7 4 7 10 12 10 10 4 5 6 8 11 11 7 6 8 10 1 1 Sinchul Sinchul Ascent of Tonglo Tambur river Sakkiazong Chateng Buckim Buckim Chateng Lachoong, 7 a.m. Lachoong, 9.50 a.m. Lachoong, noon Lachoong, 2.40 p.m. Lachoong, 4 p.m. Lachoong, sunset Lachoong, Miscellaneous Lamteng, 6 a.m. Lamteng, 9.50 a.m. Lamteng, noon Lamteng, 2.40 p.m. Lamteng, 4 p.m. Lamteng, sunset Zemu Samdong, 7 a.m. Zemu Samdong, 9.50 a.m. Zemu Samdong, noon Zemu Samdong, 2.40 p.m. Zemu Samdong, sunset Zemu Samdong, 4 p.m. Goong Tendong (top) 8607 8607 8148 8081 8353 8418 8659 8659 8752 8777 8777 8777 8777 8777 8777 8777 8884 8884 8884 8884 8884 8884 8976 8976 8976 8976 8976 8976 8999 8663 Jan. Apr. May Nov. Nov. Oct. Jan. Jan. May | | | Aug. | and | Oct. | | | May, | June, | July | and | Aug. | | | June | and | July | | Nov. May 41·7 66·8 56·2 38·0 49·7 43·8 30·2 33·9 67·2 53·3 60·2 61·6 58·1 58·6 55·5 55·9 53·9 62·8 62·8 58·3 56·2 53·3 55·7 59·7 63·1 61·0 57·9 53·8 49·0 55·5 34·3 44·6 54·4 33·9 37·4 43·2 22·8 33·1 60·7 51·1 55·3 57·1 56·4 53·8 54·3 49·6 52·0 56·2 56·2 54·4 54·7 52·5 55·3 52·8 57·1 58·6 56·1 52·6 48·5 50·0 7·4 22·2 1·8 4·1 12·3 0·6 7·4 0·8 6·5 2·2 4·9 4·5 1·7 4·8 1·2 6·3 1·9 6·6 6·6 3·9 1·5 0·8 0·4 6·9 6·0 2·4 1·8 1·2 0·5 5·5 ·216 ·310 ·434 ·213 ·241 ·299 ·143 ·207 ·536 ·388 ·447 ·475 ·464 ·424 ·432 ·368 ·400 ·461 ·461 ·435 ·438 ·407 ·448 ·412 ·473 ·500 ·459 ·407 ·355 ·373 66·3 96·9 86·8 71·7 74·0 79·2 68·6 69·8 89·7 83·0 87·1 90·1 88·0 87·5 84·5 85·9 59·5 88·3 92·0 92·2 92·3 88·1 80·4 86·3 88·0 89·6 89·3 82·7 79·7 88·6 56·9 75·4 78·9 64·1 62·4 77·5 49·4 52·2 76·8 78·9 79·9 79·4 80·0 79·4 78·7 75·2 56·4 78·7 78·0 78·4 77·1 77·4 79·8 79·0 79·8 78·2 79·0 77·3 69·1 78·1 9·4 21·5 7·9 7·6 11·6 1·7 19·2 17·6 12·9 4·1 7·2 10·7 8·0 8·1 5·8 10·7 3·1 9·6 14·0 13·8 15·2 10·7 0·6 7·3 8·2 11·4 10·3 5·4 10·6 10·5 ·472 ·866 ·967 ·599 ·566 ·926 ·366 ·403 ·904 ·967 ·999 ·983 1·007 ·981 ·959 ·858 ·464 ·959 ·939 ·950 ·914 ·922 ·997 ·969 ·994 ·944 ·970 ·920 ·705 ·943 193 Mean 54·5 50·0 4·5 ·388 83·7 73·7 9·8 ·847 East Nepal and Sikkim Calcutta Humidity Weight of vapour 0·858 4·23 gr. 0·730 8·75 gr.