Dorjiling.—Humidity 0.955 Calcutta 0.818 ,, Weight of vapour 6.25 gr. ,, 10.35 gr.

SEPTEMBER DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 28 Jillapahar, 7430 ft. 9.50 a.m. 60.8 59.3 1.5 .511 23 1848 ... Noon 62.4 60.3 2.1 .528 23 ... ... 2.40 p.m. 62.4 59.6 2.8 .516 21 ... ... 4 p.m. 62.0 59.6 2.4 .516 30 The Dale,* 6952 ft. 6 a.m. 57.4 56.2 1.2 .495 30 1848 ... 2 p.m. 64.9 60.8 4.1 .573 30 ... ... 6 p.m. 60.8 59.0 1.8 .543 ——————————————————————————————————- 185 ... ... Mean 61.5 59.3 2.3 .526 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 28 Jillapahar, 7430 ft. 9.50 a.m. 87.0 78.4 8.6 .952 23 1848 ... Noon 88.5 78.1 10.4 .943 23 ... ... 2.40 p.m. 88.1 77.4 10.7 .922 21 ... ... 4 p.m. 86.9 77.1 9.8 .914 30 The Dale,* 6952 ft. 6 a.m. 80.9 78.3 2.6 .948 30 1848 ... 2 p.m. 88.8 77.4 11.4 .923 30 ... ... 6 p.m. 84.7 76.6 8.1 .899 ——————————————————————————————————- 185 ... ... Mean 86.4 77.6 8.8 .929 ——————————————————————————————————-

Dorjiling.—Humidity 0.932 Calcutta 0.760 ,, Weight of vapour 5.72 gr. ,, 9.88 gr.

OCTOBER DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 6 Jillapahar, 7430 ft. Noon 55.9 55.3 0.6 .446 6 1848 ... 2.40 p.m. 55.7 54.9 0.8 .440 6 ... ... 4 p.m. 55.6 54.9 0.7 .441 4 Goong. 7436 ft. Misc. 48.3 48.3 0.0 .352 8 ditto 7441 ft. ditto 51.2 50.2 1.0 .376 8 The Dale* 6952 ft. 6 a.m. 55.2 52.7 2.5 .439 17 ... ... 2 p.m. 61.4 56.3 5.1 .497 19 ... ... 6 p.m. 56.9 54.2 2.7 .463 ——————————————————————————————————- 74 ... ... Mean 55.0 53.4 1.7 .432 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 6 Jillapahar, 7430 ft. Noon 84.4 75.3 9.1 .863 6 1848 ... 2.40 p.m. 86.0 73.3 12.7 .808 6 ... ... 4 p.m. 85.2 74.4 10.8 .837 4 Goong. 7436 ft. Misc. 81.2 73.7 7.5 .819 8 ditto 7441 ft. ditto 80.7 66.9 13.8 .657 8 The Dale* 6952 ft. 6 a.m. 76.1 74.2 1.9 .834 17 ... ... 2 p.m. 87.0 71.2 15.8 .756 19 ... ... 6 p.m. 82.8 73.9 8.9 .824 ——————————————————————————————————- 74 ... ... Mean 82.9 72.9 10.1 .800 ——————————————————————————————————-

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 Calcutta.

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.

SERIES II.—Observations at various Stations and Elevations in the Himalaya of East Nepal and Sikkim.

ELEVATION 735 TO 2000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Katong Ghat. 735 Dec. 60.2 55.3 4.9 .447 Teesta river 2 Great Rungeet, at bridge 818 April 82.8 63.5 19.3 .588 1 Ditto 818 May 77.8 60.3 17.5 .528 3 Tambur river, E. Nepal 1388 Nov. 60.6 57.0 3.6 .473 1 Ditto 1457 Nov. 64.2 59.1 5.1 .507 6 Bhomsong, Teesta river 1596 Dec. 58.6 52.0 6.6 .399 1 Ditto 1596 May 68.2 66.4 1.8 .647 5 Little Rungeet 1672 Jan. 51.0 50.2 0.8 .377 5 Pemiongchi, Great Rungeet 1840 Dec. 54.6 53.7 0.9 .424 11 Punkabaree 1850 March 70.1 55.6 14.5 .472 Ditto 1850 May 73.5 68.3 5.2 .687 10 Guard house 1864 April 73.7 63.8 9.9 .592 (Gt. Rungeet) ——————————————————————————————————- 48 Mean 66.3 58.8 7.5 .512

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Katong Ghat. 735 Dec. 73.2 56.7 16.5 .468 Teesta river 2 Great Rungeet, at bridge 818 April 95.8 61.9 33.9 .557 1 Ditto 818 May 91.7 78.3 13.4 .947 3 Tambur river, E. Nepal 1388 Nov. 73.3 62.7 10.6 .571 1 Ditto 1457 Nov. 77.3 63.4 13.9 .585 6 Bhomsong, Teesta river 1596 Dec. 71.6 57.0 14.6 .474 1 Ditto 1596 May 82.6 77.4 5.2 .923 5 Little Rungeet 1672 Jan. 58.5 58.0 0.5 .489 5 Pemiongchi, Great Rungeet 1840 Dec. 73.5 66.2 7.3 .642 11 Punkabaree 1850 March 79.2 62.6 16.6 .570 Ditto 1850 May 83.7 77.9 5.8 .938 10 Guard house 1864 April 92.4 67.0 25.4 .660 (Gt. Rungeet) ——————————————————————————————————- 48 Mean 79.4 65.8 13.6 .652

Humidity 0.717 Calcutta 0.663 Weight of vapour 5.57 gr. ,, 6.88 gr.

ELEVATION 2000 TO 3000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 2 Singdong 2116 Dec. 60.5 53.4 7.1 .419 8 Mywa Guola, E. Nepal 2132 Nov. 66.2 57.5 8.7 .481 3 Pemmi river, E. Nepal 2256 Nov. 55.6 53.9 1.7 .426 3 Tambur river, E. Nepal 2545 Nov. 57.3 51.6 5.7 .394 2 Blingbong (Teesta) 2684 May 72.6 64.0 8.6 .597 8 Lingo (Teesta) 2782 May 75.8 67.3 8.5 .666 12 Serriomsa (Teesta) 2820 Dec. 64.1 56.8 7.3 .469 8 Lingmo (Teesta) 2849 May 68.6 64.6 4.0 .610 3 Ditto 2952 Dec. 56.4 53.5 2.9 .420 ——————————————————————————————————- 49 Mean 64.1 58.1 6.1 .498

ELEVATION 2000 TO 3000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 2 Singdong 2116 Dec. 72.1 52.9 19.2 .411 8 Mywa Guola, E. Nepal 2132 Nov. 75.7 68.7 7.0 .697 3 Pemmi river, E. Nepal 2256 Nov. 62.9 62.3 0.6 .566 3 Tambur river, E. Nepal 2545 Nov. 75.0 63.7 11.3 .591 2 Blingbong (Teesta) 2684 May 81.7 73.6 8.1 .817 8 Lingo (Teesta) 2782 May 90.7 77.7 13.0 .932 12 Serriomsa (Teesta) 2820 Dec. 70.8 62.4 8.4 .567 8 Lingmo (Teesta) 2849 May 87.9 74.9 13.0 .851 3 Ditto 2952 Dec. 69.5 66.5 3.0 .647 ——————————————————————————————————- 49 Mean 76.3 67.0 9.3 .675

Humidity 0.820 Calcutta 0.740 Weight of vapour 5.45 gr. ,, 7.13 gr.

ELEVATION 3000 TO 4000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 5 Kulhait river 3159 Jan. 49.8 47.0 2.8 .337 9 Ratong river 3171 Jan. 44.2 43.0 1.2 .294 3 Tambur river 3201 Nov. 53.0 50.0 3.0 .373 2 Chingtam 3404 Nov. 54.8 49.0 5.8 .360 2 Tikbotang 3763 Dec. 56.5 53.4 3.1 .419 7 Myong Valley 3782 Oct. 61.4 58.4 3.0 .496 7 Iwa river 3783 Dec. 47.5 45.6 1.9 .321 1 Ratong river 3790 Jan. 56.2 41.1 15.1 .275 3 Tukcham 3849 Nov. 68.8 65.4 3.4 .625 1 Pacheem village 3855 Jan. 54.5 46.3 8.2 .329 1 Yankoon 3867 Dec. 50.0 43.6 6.4 .299 2 Mikk 3912 May 66.1 63.9 2.2 .595 5 Sunnook 3986 Dec. 47.9 45.5 2.4 .320 ——————————————————————————————————- 48 Mean 54.7 50.2 4.5 .388

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 5 Kulhait river 3159 Jan. 65.8 57.3 8.5 .477 9 Ratong river 3171 Jan. 69.9 56.6 13.3 .466 3 Tambur river 3201 Nov. 72.9 63.2 9.7 .582 2 Chingtam 3404 Nov. 74.9 73.0 1.9 .302 2 Tikbotang 3763 Dec. 68.0 61.8 6.2 .555 7 Myong Valley 3782 Oct. 80.7 71.2 9.5 .755 7 Iwa river 3783 Dec. 73.3 64.7 8.6 .611 1 Ratong river 3790 Jan. 75.8 53.0 22.8 .414 3 Tukcham 3849 Nov. 83.7 76.8 6.9 .904 1 Pacheem village 3855 Jan. 73.6 59.4 14.2 .513 1 Yankoon 3867 Dec. 69.1 63.8 5.3 .593 2 Mikk 3912 May 84.3 75.1 9.2 .856 5 Sunnook 3986 Dec. 69.4 61.1 8.3 .542 ——————————————————————————————————- 48 Mean 74.0 64.4 9.6 .621

Humidity 0.858 Calcutta 0.732 Weight of vapour 4.23 gr. ,, 6.60 gr.

ELEVATION 4000 TO 5000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Yangyading 4111 Dec. 52.0 43.6 8.4 .300 4 Gorh 4128 May. 66.4 59.0 7.4 .506 2 Namgah 4229 Oct. 57.2 54.1 3.1 .429 3 Taptiatok (Tambur) 4283 Nov. 51.3 45.8 5.5 .323 7 Myong Valley 4345 Oct. 59.1 57.8 1.3 .487 3 Jummanoo 4362 Nov. 60.4 50.0 10.4 .374 6 Nampok 4377 Dec. 49.6 49.1 0.5 .362 7 Chakoong 4407 May 57.8 57.6 0.2 .483 10 Singtam 4426 May 62.4 61.7 0.7 .553 5 Namten 4483 Dec. 44.7 44.3 0.4 .307 5 Purmiokshong 4521 Nov. 60.5 56.5 4.0 .466 2 Rungniok 4565 Jan. 54.7 44.3 10.4 .307 16 Singtam 4575 O.&N. 63.8 60.1 3.7 .525 6 Cheadam 4653 Dec. 51.4 46.6 4.8 .332 4 Sablakoo 4676 Dec. 50.0 44.9 5.2 .314 4 Bheti 4683 Nov. 59.0 52.3 6.7 .405 2 Temi 4771 May 59.8 50.1 9.7 .374 4 Lingtam 4805 May 60.4 56.6 3.8 .467 7 Khersiong 4813 Jan. 51.0 45.2 5.8 .316 6 Ditto 4813 March 53.6 45.5 8.1 .320 3 Tassiding 4840 Dec. 52.0 46.6 5.4 .333 6 Lingcham 4870 Dec. 48.5 46.1 2.4 .327 11 Dikkeeling 4952 Dec. 62.0 55.3 6.7 .447 9 Tehonpong 4978 Jan. 49.4 34.7 14.7 .219 ——————————————————————————————————- 137 Mean 55.7 50.4 5.4 .387

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Yangyading 4111 Dec. 71.1 67.2 3.9 .663 4 Gorh 4128 May. 85.5 74.2 11.3 .834 2 Namgah 4229 Oct. 80.8 73.7 7.1 .819 3 Taptiatok (Tambur) 4283 Nov. 73.3 64.8 8.5 .614 7 Myong Valley 4345 Oct. 81.7 72.9 8.8 .797 3 Jummanoo 4362 Nov. 77.4 70.2 17.2 .731 6 Nampok 4377 Dec. 64.1 56.3 7.8 .462 7 Chakoong 4407 May 83.9 76.2 7.7 .889 10 Singtam 4426 May 88.6 79.0 9.6 .969 5 Namten 4483 Dec. 64.8 58.3 6.5 .495 5 Purmiokshong 4521 Nov. 79.2 69.5 9.7 .715 2 Rungniok 4565 Jan. 66.5 59.7 16.8 .517 16 Singtam 4575 O.&N. 82.5 76.7 5.8 .901 6 Cheadam 4653 Dec. 70.2 55.0 15.2 .442 4 Sablakoo 4676 Dec. 72.9 65.7 7.2 .632 4 Bheti 4683 Nov. 78.3 66.1 12.2 .639 2 Temi 4771 May 81.2 74.1 7.1 .834 4 Lingtam 4805 May 80.0 73.8 6.2 .820 7 Khersiong 4813 Jan. 67.0 49.8 17.2 .370 6 Ditto 4813 March 77.1 70.5 6.6 .738 3 Tassiding 4840 Dec. 79.7 60.8 18.9 .538 6 Lingcham 4870 Dec. 78.5 71.8 6.7 .771 11 Dikkeeling 4952 Dec. 80.8 62.0 18.8 .559 9 Tehonpong 4978 Jan. 71.0 54.7 16.3 .439 ——————————————————————————————————- 137 Mean 76.5 66.8 9.7 .675

Humidity 0.837 Calcutta 0.730 Weight of vapour 4.33 gr. ,, 7.12 gr.

ELEVATION 5000 TO 6000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Nampok 5075 May 65.8 60.8 5.0 .537 4 Tengling 5257 Jan. 44.7 39.1 5.6 .257 2 Choongtam, sunrise 5368 May 54.9 54.7 0.2 .438 7 ,, 9.50 a.m. ,, May 71.5 58.9 12.6 .504 5 ,, noon ,, May 71.0 59.4 11.6 .513 3 ,, 2.45 p.m. ,, May 66.4 59.4 7.0 .513 4 ,, 4 p.m. ,, May 63.5 59.2 4.3 .510 6 ,, sunset ,, May 61.4 60.5 0.9 .532 8 ,, 9.50 a.m. ,, Aug. 76.3 66.1 10.2 .640 8 ,, noon ,, Aug. 78.8 67.8 11.0 .677 7 ,, 2.40 p.m. ,, Aug. 72.9 66.5 6.4 .649 6 ,, 4 p.m. ,, Aug. 69.5 66.8 2.7 .655 8 ,, sunset ,, Aug. 66.9 65.4 1.5 .627 5 Salloobong 5277 Nov. 57.6 51.2 6.4 .390 6 Lingdam 5375 Dec. 44.3 43.0 1.3 .293 3 Makaroumbi 5485 Nov. 52.1 48.1 4.0 .350 8 Khabang 5505 Dec. 55.1 47.3 7.8 .340 6 Lingdam 5554 Dec. 45.0 43.7 1.3 .301 3 Yankutang 5564 Dec. 43.6 41.7 1.9 .280 4 Namtchi 5608 May 67.1 61.2 5.9 .544 6 Yoksun 5619 Jan. 42.7 34.0 8.7 .214 16 Ditto ,, Jan. 43.0 33.9 9.1 .213 2 Loongtoong 5677 Nov. 45.3 42.8 2.5 .292 4 Sakkiazong 5625 Nov. 54.1 50.9 3.2 .358 3 Phadong 8 a.m. 5946 Nov. 51.9 50.8 1.1 .383 3 ,, 9.50 a.m. ,, Nov. 55.9 53.0 2.9 .413 3 ,, noon ,, Nov. 60.7 56.5 4.2 .465 3 ,, 2.40 p.m. ,, Nov. 57.4 54.7 2.7 .438 2 ,, 4 p.m. ,, Nov. 55.5 52.8 2.7 .410 3 ,, sunset ,, Nov. 53.7 52.6 1.1 .408 3 Tumloong 5368 Nov. 64.2 62.6 1.6 .570 22 ,, 9.50 a.m. 5976) 54.1 50.0 4.1 .375 21 ,, noon ,, ) Nov. 57.3 51.7 5.6 .396 20 ,, 2.40 p.m. ,, _ and 57.3 51.4 5.9 .391 21 ,, 4 p.m. ,, ) Dec. 54.7 50.5 4.2 .380 21 ,, sunset ,, ) 51.8 48.5 3.3 .355 ——————————————————————————————————- 260 Mean 57.7 53.3 4.5 .438

ELEVATION 5000 TO 6000 FEET. CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Nampok 5075 May 83.1 74.7 8.4 .845 4 Tengling 5257 Jan. 65.4 38.1 27.3 .247 2 Choongtam, sunrise 5368 May 78.2 73.9 4.3 .826 7 ,, 9.50 a.m. ,, May 89.8 80.0 19.8 1.000 5 ,, noon ,, May 92.7 79.9 12.8 .999 3 ,, 2.45 p.m. ,, May 95.4 78.7 16.7 .959 4 ,, 4 p.m. ,, May 93.6 79.0 14.6 .971 6 ,, sunset ,, May 89.1 77.1 12.0 .915 8 ,, 9.50 a.m. ,, Aug. 85.3 78.9 16.4 .967 8 ,, noon ,, Aug. 86.6 78.8 17.8 .965 7 ,, 2.40 p.m. ,, Aug. 86.4 78.8 7.6 .963 6 ,, 4 p.m. ,, Aug. 85.3 79.3 6.0 .980 8 ,, sunset ,, Aug. 83.6 78.5 5.1 .956 5 Salloobong 5277 Nov. 79.4 65.8 13.6 .634 6 Lingdam 5375 Dec. 68.8 59.9 8.9 .521 3 Makaroumbi 5485 Nov. 72.5 60.5 12.0 .532 8 Khabang 5505 Dec. 75.0 64.7 10.3 .611 6 Lingdam 5554 Dec. 71.0 56.5 14.5 .466 3 Yankutang 5564 Dec. 69.5 63.1 6.4 .579 4 Namtchi 5608 May 87.8 74.9 12.8 .850 6 Yoksun 5619 Jan. 68.2 58.1 10.1 .492 16 Ditto ,, Jan. 66.2 51.9 14.3 .399 2 Loongtoong 5677 Nov. 72.1 63.8 8.3 .595 4 Sakkiazong 5625 Nov. 78.3 66.1 12.2 .639 3 Phadong 8 a.m. 5946 Nov. 75.0 67.5 7.5 .670 3 ,, 9.50 a.m. ,, Nov. 80.9 67.9 13.0 .678 3 ,, noon ,, Nov. 85.6 64.8 20.8 .613 3 ,, 2.40 p.m. ,, Nov. 86.6 62.2 24.4 .562 2 ,, 4 p.m. ,, Nov. 85.5 61.9 23.6 .557 3 ,, sunset ,, Nov. 80.6 67.4 13.2 .667 3 Tumloong 5368 Nov. 83.8 77.5 6.3 .924 22 ,, 9.50 a.m. 5976) 75.1 61.9 13.2 .557 21 ,, noon ,, ) Nov. 79.7 60.1 19.6 .524 20 ,, 2.40 p.m. ,, _ and 81.3 58.0 23.3 .489 21 ,, 4 p.m. ,, ) Dec. 80.2 58.6 21.6 .499 21 ,, sunset ,, ) 76.7 61.2 15.5 .545 ——————————————————————————————————- 260 Mean 77.6 67.8 9.8 .700

Humidity 0.865 Calcutta 0.730 Weight of vapour 4.70 gr. ,, 7.34 gr.

ELEVATION 6000 TO 7000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 5 Runkpo 6008 Nov. 57.5 54.8 2.7 .440 11 Leebong 6021 Feb. 47.8 43.7 4.1 .300 11 Ditto ,, Jan. 47.8 43.4 4.4 .297 4 Dholep 6133 May 60.5 59.9 0.6 .520 2 Iwa River 6159 Dec. 41.2 40.5 0.7 .269 4 Dengha 6368 Aug. 66.7 64.0 2.7 .597 4 Kulhait River 6390 Dec. 41.9 41.9 0.0 .283 3 Latong 6391 Oct. 54.0 53.2 0.8 .416 1 Doobdi 6472 Jan. 46.6 36.2 10.4 .231 10 Pemiongchi 6584 Jan. 40.7 35.8 4.9 .228 4 Keadom 6609 Aug. 63.5 60.0 3.5 .523 6 Hee-hill 6677 Jan. 40.8 34.1 6.7 .215 7 Dumpook 6678 Jan. 40.2 31.8 8.4 .198 4 Changachelling 6828 Jan. 50.6 31.8 18.8 .198 ——————————————————————————————————- 76 Mean 50.0 45.1 4.9 .337

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 5 Runkpo 6008 Nov. 79.5 73.4 6.1 .810 11 Leebong 6021 Feb. 74.9 59.7 15.2 .517 11 Ditto ,, Jan. 66.9 56.2 10.7 .460 4 Dholep 6133 May 89.4 81.4 8.0 .046 2 Iwa River 6159 Dec. 69.6 60.2 9.4 .527 4 Dengha 6368 Aug. 86.1 78.8 7.3 .962 4 Kulhait River 6390 Dec. 71.3 60.9 10.4 .539 3 Latong 6391 Oct. 55.5 44.1 11.4 .305 1 Doobdi 6472 Jan. 78.7 58.0 20.7 .490 10 Pemiongchi 6584 Jan. 66.3 54.4 11.9 .434 4 Keadom 6609 Aug. 79.7 77.5 2.2 .925 6 Hee-hill 6677 Jan. 64.0 58.0 6.0 .489 7 Dumpook 6678 Jan. 68.5 53.8 14.7 .426 4 Changachelling 6828 Jan. 68.3 53.6 14.8 .423 ——————————————————————————————————- 76 Mean 72.8 62.1 10.6 .597

Humidity 0.845 Calcutta 0.701 Weight of vapour 3.60 gr. ,, 6.11 gr.

ELEVATION 7000 TO 8000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Pemiongchi 7083 Jan. 46.2 33.5 12.7 .210 2 Goong 7216 Nov. 49.0 48.5 0.5 .355 8 Kampo-Samdong 7329 May/ 59.1 58.2 0.9 .493 Aug. 1 Hee-hill 7289 Jan. 51.3 26.4 24.9 .163 1 Ratong river 7143 Jan. 36.5 25.3 11.2 .157 4 Source of Balasun 7436 Oct. 48.3 48.3 0.0 .352 8 Goong ridge 7441 Oct. 51.2 50.2 1.0 .376 ——————————————————————————————————- 25 Dorjiling Mean 48.8 41.5 7.3 .301

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Pemiongchi 7083 Jan. 76.8 51.8 25.0 .396 2 Goong 7216 Nov. 79.7 69.1 10.6 .705 8 Kampo-Samdong 7329 May/ 83.6 77.4 6.2 .922 Aug. 1 Hee-hill 7289 Jan. 72.8 56.6 16.2 .466 1 Ratong river 7143 Jan. 60.0 52.9 17.1 .412 4 Source of Balasun 7436 Oct. 81.2 73.7 7.5 .819 8 Goong ridge 7441 Oct. 80.7 66.9 13.8 .657 ——————————————————————————————————- 25 Dorjiling Mean 76.4 64.1 12.3 .625

From mean of above and Dorjiling: Humidity 0.826 Calcutta 0.668 Weight of vapour 3.85 gr. ,, 7.28 gr.

ELEVATION 8000 TO 9000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Sinchul 8607 Jan. 41.7 34.3 7.4 .216 2 Ditto ,, April 66.8 44.6 22.2 .310 1 Ascent of Tonglo 8148 May 56.2 54.4 1.8 .434 2 Tambur river 8081 Nov. 38.0 33.9 4.1 .213 3 Sakkiazong 8353 Nov. 49.7 37.4 12.3 .241 4 Chateng 8418 Oct. 43.8 43.2 0.6 .299 6 Buckim 8659 Jan. 30.2 22.8 7.4 .143 9 Ditto ,, Jan. 33.9 33.1 0.8 .207 1 Chateng 8752 May 67.2 60.7 6.5 .536 11 Lachoong 7 a.m. 8777) 53.3 51.1 2.2 .388 12 ,, 9.50 a.m. ,, ) 60.2 55.3 4.9 .447 7 ,, noon ,, ) Aug. 61.6 57.1 4.5 .475 4 ,, 2.40 p.m. ,, _ and 58.1 56.4 1.7 .464 7 ,, 4 p.m. ,, ) Oct. 58.6 53.8 4.8 .424 10 ,, sunset ,, ) 55.5 54.3 1.2 .432 12 ,, Miscellaneous ,, ) 55.9 49.6 6.3 .368 10 Lamteng 6 a.m. 8884) May 53.9 52.0 1.9 .400 10 ,, 9.50 a.m. ,, ) June 62.8 56.2 6.6 .461 4 ,, noon ,, _ July 62.8 56.2 6.6 .461 5 ,, 2.40 p.m. ,, ) and 58.3 54.5 3.9 .435 6 ,, 4 p.m. ,, ) Aug. 56.2 54.7 1.5 .438 8 ,, sunset ,, ) 53.3 52.5 0.8 .407 11 Zemu Sundong 7 a.m. 8976) 55.7 55.3 0.4 .448 11 ,, 9.50 a.m. ,, ) June 59.7 52.8 6.9 .412 7 ,, noon ,, ) and 63.1 57.1 6.0 .473 6 ,, 2.40 p.m. ,, _ July 61.0 58.6 2.4 .500 8 ,, sunset ,, ) 57.9 56.1 1.8 .459 10 ,, 4 p.m. ,, ) 53.8 52.6 1.2 .407 1 Goong 8999 Nov. 49.0 48.5 0.5 .355 1 Tendong (top) 8663 May 55.5 50.0 5.5 .373 ——————————————————————————————————- 193 Mean 54.5 50.0 4.5 .388

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Sinchul 8607 Jan. 66.3 56.9 9.4 .472 2 Ditto ,, April 96.9 75.4 21.5 .866 1 Ascent of Tonglo 8148 May 86.8 78.9 7.9 .967 2 Tambur river 8081 Nov. 71.7 64.1 7.6 .599 3 Sakkiazong 8353 Nov. 74.0 62.4 11.6 .566 4 Chateng 8418 Oct. 79.2 77.5 1.7 .926 6 Buckim 8659 Jan. 68.6 49.4 19.2 .366 9 Ditto ,, Jan. 69.8 52.2 17.6 .403 1 Chateng 8752 May 89.7 76.8 12.9 .904 11 Lachoong 7 a.m. 8777) 83.0 78.9 4.1 .967 12 ,, 9.50 a.m. ,, ) 87.1 79.9 7.2 .999 7 ,, noon ,, ) Aug. 90.1 79.4 10.7 .983 4 ,, 2.40 p.m. ,, _ and 88.0 80.0 8.0 1.007 7 ,, 4 p.m. ,, ) Oct. 87.5 79.4 8.1 .981 10 ,, sunset ,, ) 84.5 78.7 5.8 .959 12 ,, Miscellaneous ,, ) 85.9 75.2 10.7 .858 10 Lamteng 6 a.m. 8884) May 59.5 56.4 3.1 .464 10 ,, 9.50 a.m. ,, ) June 88.3 78.7 9.6 .959 4 ,, noon ,, ) July 92.0 78.0 14.0 .939 5 ,, 2.40 p.m. ,, _ and 92.2 78.4 13.8 .950 6 ,, 4 p.m. ,, ) Aug. 92.3 77.1 15.2 .914 8 ,, sunset ,, ) 88.1 77.4 10.7 .922 11 Zemu Sundong 7 a.m. 8976) 80.4 79.8 0.6 .997 11 ,, 9.50 a.m. ,, ) June 86.3 79.0 7.3 .969 7 ,, noon ,, _ and 88.0 79.8 8.2 .994 6 ,, 2.40 p.m. ,, ) July 89.6 78.2 11.4 .944 8 ,, sunset ,, ) 89.3 79.0 10.3 .970 10 ,, 4 p.m. ,, ) 82.7 77.3 5.4 .920 1 Goong 8999 Nov. 79.7 69.1 10.6 .705 1 Tendong (top) 8663 May 88.6 78.1 10.5 .943 ——————————————————————————————————- 193 Mean 83.7 73.7 9.8 .847

Humidity 0.858 Calcutta 0.730 Weight of vapour 4.23 gr. ,, 8.75 gr.

ELEVATION 9000 TO 10,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Yangma Guola 9279 Nov. 37.8 33.1 4.7 .207 8 Nanki 9320 Nov. 42.3 38.2 4.0 .249 4 Singalelah 9295 Dec. 36.2 35.7 0.5 .227 1 Sakkiazong 9322 Nov. 53.5 33.3 20.2 .209 1 Zemu river 9828 June 60.0 47.6 12.4 .343 ——————————————————————————————————- 18 Mean 46.0 37.6 8.4 .247

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 4 Yangma Guola 9279 Nov. 72.7 61.4 11.3 .549 8 Nanki 9320 Nov. 52.2 48.3 3.9 .352 4 Singalelah 9295 Dec. 70.9 62.1 8.8 .560 1 Sakkiazong 9322 Nov. 80.0 57.3 22.7 .478 1 Zemu river 9828 June 93.3 81.9 11.4 1.062 ——————————————————————————————————- 18 Mean 73.8 62.2 11.6 .600

Humidity 0.860 Calcutta 0.760 Weight of vapour 3.46 gr. ,, 9.00 gr.

ELEVATION 10,000 TO 11,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 13 Tonglo 10,008 May 51.5 50.2 1.3 .376 3 Nanki 10,024 Nov. 42.8 35.5 7.3 .225 4 Yalloong river 10,058 Dec. 37.7 29.6 8.1 .183 2 Tonglo top 10,079 May 49.9 47.9 2.0 .348 2 Yeunga 10,196 Oct. 45.9 44.7 1.2 .311 4 Zemu river 10,247 June 45.4 44.2 1.2 .306 10 Wallanchoon 10,348 Nov. 37.9 30.2 7.7 .187 4 Laghep 10,423 Nov. 46.0 42.4 3.6 .287 3 Ditto ,, Nov. 37.6 37.0 0.6 .238 16 Thlonok river 7 a.m. 10,846 June 48.5 47.2 1.3 .339 17 ,, 9.50 a.m. ,, June 57.6 51.4 6.2 .392 9 ,, noon ,, June 56.1 50.6 5.5 .382 8 ,, 2.40 p.m. ,, June 54.8 50.6 4.2 .381 9 ,, 4 p.m. ,, June 53.4 50.6 2.8 .381 15 ,, sunset ,, June 49.8 48.9 0.9 .359 4 Yangma Valley 10,999 Dec. 31.6 24.3 7.3 .149 ——————————————————————————————————- 123 Mean 46.7 42.8 3.8 .303

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 13 Tonglo 10,008 May 88.8 80.8 8.0 1.030 3 Nanki 10,024 Nov. 79.5 65.8 13.7 .633 4 Yalloong river 10,058 Dec. 77.7 62.1 15.6 .560 2 Tonglo top 10,079 May 89.4 80.5 8.9 1.018 2 Yeunga 10,196 Oct. 79.5 77.1 2.4 .915 4 Zemu river 10,247 June 84.6 75.1 9.5 .856 10 Wallanchoon 10,348 Nov. 76.5 61.9 14.6 .558 4 Laghep 10,423 Nov. 80.9 68.0 12.9 .681 3 Ditto ,, Nov. 75.3 69.4 5.9 .712 16 Thlonok river 7 a.m. 10,846 June 79.0 75.1 3.9 .856 17 ,, 9.50 a.m. ,, June 87.4 78.8 8.6 .965 9 ,, noon ,, June 90.0 79.3 10.7 .979 8 ,, 2.40 p.m. ,, June 88.5 79.7 8.8 .991 9 ,, 4 p.m. ,, June 88.7 78.7 10.0 .962 15 ,, sunset ,, June 85.5 78.0 7.5 .938 4 Yangma Valley 10,999 Dec. 74.4 61.9 12.3 .558 ——————————————————————————————————- 123 Mean 82.8 73.3 9.5 .826

Humidity 0.878 Calcutta 0.740 Weight of vapour 3.35 gr. ,, 8.70 gr.

ELEVATION 11,000 TO 12,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Barfonchen 11,233 Nov. 36.8 31.9 4.9 .198 3 Punying 11,299 Aug. 50.2 49.5 0.7 .367 1 Kambachen village 11,378 Dec. 43.3 32.5 10.8 .203 12 Tallum 7 a.m. 11,482 July 50.4 47.8 2.6 .347 6 ,, 9.50 a.m. ,, July 58.1 50.5 7.6 .380 8 ,, noon ,, July 57.9 50.8 7.1 .384 5 ,, 2.40 p.m. ,, July 55.7 50.2 5.5 .377 6 ,, 4 p.m. ,, July 54.3 50.1 4.2 .375 6 ,, sunset ,, July 48.8 47.3 1.5 .340 2 Kambachen valley 11,484 Dec. 30.4 26.0 4.4 .161 10 Yeumtong 7 a.m. 11,887) 44.4 43.8 0.6 .302 9 ,, 9.50 a.m. ,, ) Aug. 53.6 48.9 4.7 .360 5 ,, noon ,, ) Sep. 54.5 48.3 6.2 .353 7 ,, 2.40 p.m. ,, _ and 48.8 47.4 1.4 .342 4 ,, 4 p.m. ,, ) Oct. 48.4 47.1 1.3 .338 10 ,, sunset ,, ) 42.0 35.9 6.1 .229 7 ,, Miscellaneous ,, Oct. 43.5 37.1 6.4 .239 ——————————————————————————————————- 104 Mean 48.3 43.8 4.5 .311

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 3 Barfonchen 11,233 Nov. 76.3 69.6 6.7 .719 3 Punying 11,299 Aug. 84.5 78.8 5.7 .963 1 Kambachen village 11,378 Dec. 80.0 61.2 18.8 .544 12 Tallum 7 a.m. 11,482 July 85.0 80.3 4.7 1.010 6 ,, 9.50 a.m. ,, July 88.1 79.7 8.4 .993 8 ,, noon ,, July 89.7 81.3 8.4 1.043 5 ,, 2.40 p.m. ,, July 89.3 80.6 8.7 1.020 6 ,, 4 p.m. ,, July 90.3 79.4 10.9 .981 6 ,, sunset ,, July 86.6 80.0 6.6 1.001 2 Kambachen valley 11,484 Dec. 69.9 59.5 10.4 .515 10 Yeumtong 7 a.m. 11,887) 83.0 78.9 4.1 .967 9 ,, 9.50 a.m. ,, ) Aug. 87.5 78.7 8.8 .959 5 ,, noon ,, ) Sep. 89.7 77.2 12.5 .917 7 ,, 2.40 p.m. ,, _ and 87.2 77.2 10.0 .915 4 ,, 4 p.m. ,, ) Oct. 85.2 77.8 7.4 .934 10 ,, sunset ,, ) 60.6 58.5 2.1 .497 7 ,, Miscellaneous ,, Oct. 83.7 69.7 14.0 .720 ——————————————————————————————————- 104 Mean 83.3 74.6 8.7 .865

Humidity 0.860 Calcutta 0.760 Weight of vapour 3.46 gr. ,, 9.00 gr.

ELEVATION 12,000 TO 13,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 9 Zemu river 7 a.m. 12,070) 46.6 45.6 1.0 .321 9 ,, 9.50 a.m. ,, ) June 51.1 49.0 2.1 .362 7 ,, noon ,, _ and 51.1 50.2 0.9 .376 7 ,, 2.40 p.m. ,, ) July 51.2 50.3 0.9 .377 7 ,, 4 p.m. ,, ) 49.7 48.9 0.8 .360 8 ,, sunset ,, ) 48.1 47.6 0.5 .344 2 Yangma Valley 12,129 Nov. 34.8 22.7 12.1 .143 1 Zemu river 12,422 June 49.0 46.6 2.4 .332 3 Chumanako 12,590 Nov. 37.3 28.3 9.0 .174 7 Tungu 7 a.m. 12,751 July 45.1 44.1 1.0 .305 5 ,, 9.50 a.m. ,, July 53.1 48.6 4.5 .355 1 ,, noon ,, July 62.3 52.7 9.6 .409 1 ,, 2.40 p.m. ,, July 60.0 53.8 6.2 .425 6 ,, sunset ,, July 46.4 45.3 1.1 .317 3 ,, sunrise ,, Oct. 38.2 35.0 3.2 .222 4 ,, 9.50 a.m. ,, Oct. 46.5 42.8 3.7 .292 4 ,, noon ,, Oct. 46.1 42.0 4.1 .284 4 ,, 2.40 p.m. ,, Oct. 43.8 42.1 1.7 .285 4 ,, 4 p.m. ,, Oct. 42.3 40.8 1.5 .271 6 ,, sunset ,, Oct. 41.0 38.7 2.3 .253 23 ,, Miscellaneous ,, Oct. 43.2 40.8 2.4 .272 13 ,, Ditto ,, July 51.3 47.4 3.6 .345 6 Tuquoroma 12,944 Nov. 26.0 23.4 2.6 .146 ——————————————————————————————————- 140 Mean 46.3 42.9 3.4 .303

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 9 Zemu river 7 a.m. 12,070) 80.6 77.7 2.9 .931 9 ,, 9.50 a.m. ,, ) June 84.5 75.1 9.4 .972 7 ,, noon ,, _ and 87.0 82.2 4.8 1.074 7 ,, 2.40 p.m. ,, ) July 86.3 80.0 6.3 1.000 7 ,, 4 p.m. ,, ) 86.5 80.2 6.3 1.006 8 ,, sunset ,, ) 81.4 77.5 3.9 .926 2 Yangma Valley 12,129 Nov. 70.6 63.7 16.9 .592 1 Zemu river 12,422 June 93.2 79.6 13.6 .989 3 Chumanako 12,590 Nov. 75.1 73.8 1.3 .822 7 Tungu 7 a.m. 12,751 July 80.5 78.3 2.2 .949 5 ,, 9.50 a.m. ,, July 87.1 79.4 7.7 .982 1 ,, noon ,, July 88.9 77.8 11.1 .935 1 ,, 2.40 p.m. ,, July 85.3 79.5 5.8 .985 6 ,, sunset ,, July 84.7 79.1 5.6 .974 3 ,, sunrise ,, Oct. 79.4 77.8 1.6 .932 4 ,, 9.50 a.m. ,, Oct. 85.0 78.6 6.4 .957 4 ,, noon ,, Oct. 85.0 78.2 6.8 .944 4 ,, 2.40 p.m. ,, Oct. 86.4 78.8 7.6 .963 4 ,, 4 p.m. ,, Oct. 85.9 78.5 7.4 .956 6 ,, sunset ,, Oct. 83.3 78.2 5.1 .947 23 ,, Miscellaneous ,, Oct. 84.5 78.4 6.1 .950 13 ,, Ditto ,, July 85.7 79.0 6.7 .971 6 Tuquoroma 12,944 Nov. 75.1 60.8 14.3 .537 ——————————————————————————————————- 140 Mean 83.6 77.1 6.5 .926

Humidity 0.890 Calcutta 0.815 Weight of vapour 3.37 gr. ,, 9.75 gr.

ELEVATION 13,000 TO 14,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 7 Mon Lepcha 13,090 Jan. 27.1 18.5 8.6 .122 4 Ditto 13,073 Jan. 25.6 16.4 9.2 .113 2 Tunkra valley 13,111 Aug. 45.0 43.5 1.5 .298 21 Jongri 13,194 Jan. 22.7 10.5 12.2 .091 1 Zemu river 13,281 June 46.7 46.7 0.0 .334 4 Choonjerma 13,288 Dec. 39.0 11.1 27.9 .093 10 Yangma village 13,502 Nov./ 33.8 18.6 15.2 .123 Dec. 1 Wallanchoon road 13,505 Nov. 28.0 9.5 18.5 .088 3 Kambachen, below pass 13,600 Dec. 40.0 18.6 21.4 .123 ——————————————————————————————————- 53 Mean 34.2 21.5 12.6 .154

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 7 Mon Lepcha 13,090 Jan. 70.0 50.8 19.2 .527 4 Ditto 13,073 Jan. 71.7 49.9 21.8 .373 2 Tunkra valley 13,111 Aug. 81.2 78.7 2.5 .962 21 Jongri 13,194 Jan. 70.6 53.2 17.4 .417 1 Zemu river 13,281 June 92.9 86.6 6.2 1.230 4 Choonjerma 13,288 Dec. 69.8 61.8 28.0 .555 10 Yangma village 13,502 Nov./ 78.9 62.1 16.8 .561 Dec. 1 Wallanchoon road 13,505 Nov. 66.4 61.8 14.6 .555 3 Kambachen, below pass 13,600 Dec. 72.9 62.2 10.7 .563 ——————————————————————————————————- 53 Mean 74.9 63.0 11.9 .636

Humidity 0.634 Calcutta 0.678 Weight of vapour 1.61 gr. 6.28 gr.

ELEVATION 15,000 TO 16,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Yangma valley 15,186 Dec. 42.2 20.7 21.5 .133 1 Choonjerma pass 15,259 Dec. 34.3 10.5 23.8 .091 8 Lachee-pia 15,262 Aug. 42.0 41.6 0.4 .279 12 Momay, 7 a.m. ,, Sept. 39.4 34.7 4.7 .219 6 ,, 9.50 a.m. ,, Sept. 50.9 41.7 9.2 .280 4 ,, noon ,, Sept. 51.7 43.6 8.1 .299 8 ,, 2.40 p.m. ,, Sept. 49.7 41.9 7.8 .283 10 ,, 4 p.m. ,, Sept. 44.4 41.3 3.1 .276 16 ,, sunset ,, Sept. 41.5 38.6 2.9 .252 8 ,, Miscellaneous ,, Sept. 47.6 41.4 6.2 .277 6 ,, ,, ,, Oct. 40.9 36.5 4.4 .234 3 Sittong 15,372 Oct. 38.6 29.8 8.8 .184 2 Palung 15,676 Oct. 44.6 39.8 4.8 .262 1 Kambachen pass 15,770 Dec. 26.5 15.9 10.6 .111 1 Yeumtong 15,985 Sept. 44.6 43.7 0.9 .300 ——————————————————————————————————- 87 Mean 42.6 34.8 7.8 .232

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Yangma valley 15,186 Dec. 80.8 62.0 18.8 .559 1 Choonjerma pass 15,259 Dec. 77.9 60.6 17.3 .534 8 Lachee-pia 15,262 Aug. 85.5 79.4 6.1 .982 12 Momay, 7 a.m. ,, Sept. 80.5 78.8 1.7 .966 6 ,, 9.50 a.m. ,, Sept. 87.6 78.8 8.8 .963 4 ,, noon ,, Sept. 89.5 79.7 9.8 .990 8 ,, 2.40 p.m. ,, Sept. 90.0 78.3 11.7 .949 10 ,, 4 p.m. ,, Sept. 88.7 77.6 11.1 .928 16 ,, sunset ,, Sept. 84.2 78.4 5.8 .952 8 ,, Miscellaneous ,, Sept. 87.4 78.6 8.8 .956 6 ,, ,, ,, Oct. 83.9 69.3 14.6 .710 3 Sittong 15,372 Oct. 84.0 77.5 6.5 .926 2 Palung 15,676 Oct. 86.8 78.5 8.3 .954 1 Kambachen pass 15,770 Dec. 78.0 58.5 19.5 .498 1 Yeumtong 15,985 Sept. 88.8 80.5 8.3 1.016 ——————————————————————————————————- 87 Mean 84.9 74.4 10.5 .859

Humidity 0.763 Calcutta 0.719 Weight of vapour 2.55 gr. 8.95 gr.

ELEVATION 16,000 TO 17,000 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Kanglachem pass 16,038 Dec. 32.8 16.3 16.5 .110 3 Tunkra pass 16,038 Aug. 39.8 38.7 1.1 .252 1 Wallanchoon pass 16,756 Nov. 18.0-6.0 24.0 .046 5 Teumtso 16,808 Oct. 32.4 25.1 7.3 .156 6 Cholamoo lake 16,900 Oct. 31.4 20.2 11.2 .130 1 Donkia mountain 16,978 Sept. 40.2 25.9 14.3 .160 ——————————————————————————————————- 17 Mean 32.4 20.0 12.4 .142

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Kanglachem pass 16,038 Dec. 80.7 61.1 19.6 .543 3 Tunkra pass 16,038 Aug. 86.0 78.7 7.3 .959 1 Wallanchoon pass 16,756 Nov. 79.9 57.6 22.3 .483 5 Teumtso 16,808 Oct. 85.0 75.7 9.3 .872 6 Cholamoo lake 16,900 Oct. 79.8 68.4 11.4 .690 1 Donkia mountain 16,978 Sept. 87.6 78.8 18.8 .963 ——————————————————————————————————- 17 Mean 83.2 70.1 13.3 .752

Humidity 0.640 Calcutta 0.658 Weight of vapour 1.53 gr. 7.80 gr.

ELEVATION 17,000 TO 18,500 FEET. EASTERN NEPAL AND SIKKIM. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Kinchinjhow 17,624 Sept. 47.5 30.9 16.6 .191 1 Sebolah pass 17,585 Sept. 46.5 34.6 11.9 .218 1 Donkin mountain 18,307 Sept. 38.8 35.3 3.5 .224 3 Bhomtso 18,450 Oct. 54.0 4.4 49.6 .072 2 Donkia pass 18,466 Sept. 41.8 30.3 11.5 .188 2 Ditto 18,466 Oct. 40.1 25.0 15.1 .155 ——————————————————————————————————- 10 Mean 44.8 26.8 18.0 .175

CALCUTTA. No. of Obs. Locality Elev. Month Tem. D.P. Diff. Tens ——————————————————————————————————- 1 Kinchinjhow 17,624 Sept. 85.7 79.7 16.0 .991 1 Sebolah pass 17,585 Sept. 88.8 80.0 18.8 1.002 1 Donkin mountain 18,307 Sept. 90.7 79.3 11.4 .981 3 Bhomtso 18,450 Oct. 91.1 61.1 20.0 .543 2 Donkia pass 18,466 Sept. 84.1 78.4 15.7 .950 2 Ditto 18,466 Oct. 86.5 65.5 21.0 .627 ——————————————————————————————————- 10 Mean 87.8 74.0 12.2 .849

Humidity 0.532 Calcutta 0.648 Weight of vapour 1.90 gr. 8.78 gr.

SUMMARY.

HUMIDITY WEIGHT OF VAPOUR No. of Elevations Sta- Sik-Cal- Diff. Sik-Cal-Diff. Obs. in Feet tions kim cutta Sikkim kim cutta Sikkim ——————————————————————————————————— 48 735 to 2000 9 .717 .663 +.054 5.57 6.88-1.31 49 2000 to 3000 9 .820 .740 .080 5.45 7.13 1.68 48 3000 to 4000 13 .858 .732 .116 4.23 6.60 2.37 137 4000 to 5000 23 .837 .730 .107 4.33 7.12 2.79 260 5000 to 6000 15 .865 .730 .135 4.70 7.34 2.64 76 6000 to 7000 13 .845 .701 .144 3.60 6.71 3.11 1023 7000 to 8000 14 .826 .668 .158 3.85 7.28 3.43 193 8000 to 9000 13 .858 .730 .128 4.23 8.75 4.52 18 9000 to 10,000 5 .747 .724 .023 2.80 6.28 3.48 123 10,000 to 11,000 10 .878 .740 .138 3.35 8.70 4.35 104 11,000 to 12,000 6 .860 .760 .100 3.46 9.00 5.54 140 12,000 to 13,000 6 .890 .815 .075 3.37 9.75 6.38 53 13,000 to 14,000 9 .634 .678 -.044 1.61 6.28 4.67 87 15,000 to 16,000 8 .763 .719 +.044 2.55 8.95 6.40 17 16,000 to 17,000 6 .640 .658 .018 1.53 7.80 6.27 10 17,000 to 18,500 5 .532 .648 -.116 1.90 8.78 6.88 ——————————————————————————————————— 2386 154

Considering how desultory the observations in Sikkim are, and how much affected by local circumstances, the above results must be considered highly satisfactory: they prove that the relative humidity of the atmospheric column remains pretty constant throughout all elevations, except when these are in a Tibetan climate; and when above 18,000 feet, elevations which I attained in fine weather only. Up to 12,000 feet this constant humidity is very marked; the observations made at greater elevations were almost invariably to the north, or leeward of the great snowy peaks, and consequently in a drier climate; and there it will be seen that these proportions are occasionally inverted; and in Tibet itself a degree of relative dryness is encountered, such as is never equalled on the plains of Eastern Bengal or the Gangetic delta. Whether an isolated peak rising near Calcutta, to the elevation of 19,000 feet, would present similar results to the above, is not proven by these observations, but as the relative humidity is the same at all elevations on the outermost ranges of Sikkim, which attain 10,000 feet, and as these rise from the plains like steep islands out of the ocean, it may be presumed that the effects of elevation would be the same in both cases.

The first effect of this humid wind is to clothe Sikkim with forests, that make it moister still; and however difficult it is to separate cause from effect in such cases as those of the reciprocal action of humidity on vegetation, and vegetation on humidity, it is necessary for the observer to consider the one as the effect of the other. There is no doubt that but for the humidity of the region, the Sikkim Himalaya would not present the uniform clothing of forest that it does; and, on the other hand, that but for this vegetation, the relative humidity would not be so great.* [Balloon ascents and observations on small mountainous islands, therefore, offer the best means of solving such questions: of these, the results of ballooning, under Mr. Welsh's intrepid and skilful pioneering (see Phil. Trans. for 1853), have proved most satisfactory; though, from the time for observation being short, and from the interference of belts of vapour, some anomalies have not been eliminated. Islands again are still more exposed to local influences, which may be easily eliminated in a long series of observations. I think that were two islands, as different in their physical characters as St. Helena and Ascension, selected for comparative observations, at various elevations, the laws that regulate the distribution of humidity in the upper regions might be deduced without difficulty. They are advantageous sites, from differing remarkably in their humidity. Owing partly to the indestructible nature of its component rock (a glassy basalt), the lower parts of Ascension have never yielded to the corroding effects of the moist sea air which surrounds it; which has decomposed the upper part into a deep bed of clay. Hence Ascension does not support a native tree, or even shrub, two feet high. St. Helena, on the other hand, which can hardly be considered more favourably situated for humidity, was clothed with a redundant vegetation when discovered, and trees and tree-ferns (types of humidity) still spread over its loftiest summits. Here the humidity, vegetation, and mineral and mechanical composition reciprocate their influences.]

The great amount of relative humidity registered at 6000 to 8000 feet, arises from most of the observations having been made on the outer range, where the atmosphere is surcharged. The majority of those at 10,000 to 12,000 feet, which also give a disproportionate amount of humidity, were registered at the Zemu and Thlonok rivers, where the narrowness of the valleys, the proximity of great snowy peaks, and the rank luxuriance of the vegetation, all favour a humid atmosphere.

I would have added the relative rain-fall to the above, but this is so very local a phenomenon, and my observations were so repeatedly deranged by having to camp in forests, and by local obstacles of all kinds, that I have suppressed them; their general results I have given in Appendix F.

I here add a few observations, taken on the plains at the foot of the Sikkim Himalaya during the spring months.

Comparison between Temperature and Humidity of the Sikkim Terai and Calcutta, in March and April, 1849.

Elev. No. above TEMP. D.P. TENSION SAT. of sea. Obs. Locality Feet C. T. C. T. C. T. C. T. ——————————————————————————————————- 4 Rummai 293 82.2 70.6 61.7 60.5 .553 .532 .517 .717 4 Belakoba 368 92.8 85.5 62.6 63.0 .570 .578 .382 .485 3 Rangamally 275 84.2 75.0 68.7 62.5 .695 .568 .605 .665 3 Bhojepore 404 90.1 81.2 54.1 44.3 .429 .308 .313 .295 4 Thakyagunj 284 84.9 77.1 61.3 60.8 .547 .537 .466 .588 3 Bhatgong 225 87.4 74.9 64.7 54.6 .611 .436 .480 .512 2 Sahigunj 231 80.2 68.0 66.2 53.1 .642 .414 .635 .409 8 Titalya 362 85.5 80.0 55.4 56.1 .448 .459 .376 .459 ——————————————————————————————————- 31 Means 305 85.9 79.0 61.8 56.9 .562 .479 .472 .516 May, 1850 ) 131 89.7 K78.6 76.7 K71.4 .904 K.759 .665 K.793 Kishengunj) ——————————————————————————————————- Vapour in a cubic foot—Kishengunj 8.20 Terai 5.08 Calcutta 9.52 Calcutta 5.90 Mean difference of temperature between Terai and Calcutta, from 31 observations in March, as above, excluding minima Terai—6.9 Mean difference from 26 observations in March, including minima Terai—9.7 Mean difference of temperature at Siligore on May 1, 1850— 10.9 Mean difference of temperature at Kishengunj on May 1, 1850—11.1

From the above, it appears that during the spring months, and before the rains commence, the belt of sandy and grassy land along the Himalaya, though only 3.5 degrees north of Calcutta, is at least 6 degrees or 7 degrees colder, and always more humid relatively, though there is absolutely less moisture suspended in the air. After the rains commence; I believe that this is in a great measure inverted, the plains becoming excessively heated, and the temperature being higher than at Calcutta. This indeed follows from the well known fact that the summer heat increases greatly in advancing north-west from the Bay of Bengal to the trans-Sutledge regions; it is admirably expressed in the maps of Dove's great work "On the Distribution of Heat on the Surface of the Globe."

APPENDIX H.

ON THE TEMPERATURE OF THE SOIL AT VARIOUS ELEVATIONS.

These observations were taken by burying a brass tube two feet six inches to three feet deep, in exposed soil, and sinking in it, by a string or tied to a slip of wood, a thermometer whose bulb was well padded with wool: this, after a few hours' rest, indicates the temperature of the soil. Such a tube and thermometer I usually caused to be sunk wherever I halted, if even for one night, except during the height of the rains, which are so heavy that they communicate to the earth a temperature considerably above that of the air.

The results proved that the temperature of the soil at Dorjiling varies with that of the month, from 46 degrees to 62.2 degrees, but is hardly affected by the diurnal variation, except in extreme cases. In summer, throughout the rains, May to October, the temperature is that of the month, which is imparted by the rain to the depth of eleven feet during heavy continued falls (of six to twelve inches a day), on which occasions I have seen the buried thermometer indicating a temperature above the mean of the month. Again, in the winter months, December and January, it stands 5 degrees above the monthly mean; in November and February 4 degrees to 5 degrees; in March a few degrees below the mean temperature of the month, and in October above it; April and May being sunny, it stands above their mean; June to September a little below the mean temperature of each respectively.

The temperature of the soil is affected by:—1. The exposure of the surface; 2. The nature of the soil; 3. Its permeability by rain, and the presence of underground springs; 4. The sun's declination; 5. The elevation above the sea, and consequently the heating power of the sun's rays: and 6, The amount of cloud and sunshine.

The appended observations, though taken at sixty-seven places, are far from being sufficient to supply data for the exact estimation of the effects of the sun on the soil at any elevation or locality; they, however, indicate with tolerable certainty the main features of this phenomenon, and these are in entire conformity with more ample series obtained elsewhere. The result, which at first sight appears the most anomalous, is, that the mean temperature of the soil, at two or three feet depth, is almost throughout the year in India above that of the surrounding atmosphere. This has been also ascertained to be the case in England by several observers, and the carefully conducted observations of Mr. Robert Thompson at the Horticultural Society's Gardens at Chiswick, show that the temperature of the soil at that place is, on the mean of six years, at the depth of one foot, 1 degree above that of the air, and at two feet 1.5 degrees. During the winter months the soil is considerably (l degree to 3 degrees) warmer than the air, and during summer the soil is a fraction of a degree cooler than the air.

In India, the sun's declination being greater, these effects are much exaggerated, the soil on the plains being in winter sometimes 9 degrees hotter than the air; and at considerable elevations in the Himalaya very much more than that; in summer also, the temperature of the soil seldom falls below that of the air, except where copious rain-falls communicate a low temperature, or where forests interfere with the sun's rays.

At considerable elevations these effects are so greatly increased, that it is extremely probable that at certain localities the mean temperature of the soil may be even 10 degrees warmer than that of the air; thus, at Jongri, elevation 13,194 feet, the soil in January was 34.5 degrees, or 19.2 degrees above the mean temperature of the month, immediately before the ground became covered with snow for the remainder of the winter; during the three succeeding months, therefore, the temperature of the soil probably does not fall below that of the snow, whilst the mean temperature of the air in January may be estimated at about 20 degrees, February 22 degrees, March 30 degrees, and April 35 degrees. If, again, we assume the temperature of the soil of Jongri to be that of other Sikkim localities between 10,000 and 14,000 feet, we may assume the soil to be warmer by 10 degrees in July (see Tungu observations), by 8 degrees or 9 degrees in September (see Yeumtong); by l0 degrees in October (see Tungu); and by 7 degrees to l0 degrees in November (see Wallanchoon and Nanki). These temperatures, however, vary extremely according to exposure and amount of sunshine; and I should expect that the greatest differences would be found in the sunny climate of Tibet, where the sun's heat is most powerful. Were nocturnal or terrestrial radiation as constant and powerful as solar, the effects of the latter would be neutralised; but such is not the case at any elevation in Sikkim.

This accumulated heat in the upper strata of soil must have a very powerful effect upon vegetation, preventing the delicate rootlets of shrubs from becoming frozen, and preserving vitality in the more fleshy, roots, such as those of the large rhubarbs and small orchids, whose spongy cellular tissues would no doubt be ruptured by severe frosts. To the burrowing rodents, the hares, marmots, and rats, which abound at 15,000 to 17,000 feet in Tibet, this phenomenon is even more conspicuously important; for were the soil in winter to acquire the mean temperature of the air, it would take very long to heat after the melting of the snow, and indeed the latter phenomenon would be greatly retarded. The rapid development of vegetation after the disappearance of the snow, is no doubt also proximately due to the heat of the soil, quite as much as to the increased strength of the sun's direct rays in lofty regions.

I have given in the column following that containing the temperature of the sunk thermometer, first the extreme temperatures of the air recorded during the time the instrument was sunk; and in the next following, the mean temperature of the air during the same period, so far as I could ascertain it from my own observations.

SERIES I.—Soane Valley ——————————————————————————————————- Locality Muddunpore Date Feb. 11 to 12 Elevation 440 feet Depth 3 ft. 4 in. Temp. of sunk Therm. 71.5 Extreme Temperature of Air observed 62.0 to 77.5 Approximate Mean Temp. of Air deduced 67.0 Diff. between Air and sunk Therm. +4.5 ——————————————————————————- Locality Nourunga Date Feb. 12 to 13 Elevation 340 feet Depth 3 ft. 8 in. Temp. of sunk Therm. 71.7 Extreme Temperature of Air observed 57.0 to 71.5 Approximate Mean Temp. of Air deduced 67.3 Diff. between Air and sunk Therm. 3.4 ——————————————————————————- Locality Baroon Date Feb. 13 to 14 Elevation 345 feet Depth 2 ft. 4 in. Temp. of sunk Therm. 68.5 Extreme Temperature of Air observed 53.5 to 76.0 Approximate Mean Temp. of Air deduced 67.6 Diff. between Air and sunk Therm. 1.9 ——————————————————————————- Locality Tilotho Date Feb. 15 to 16 Elevation 395 feet Depth 4 ft. 6 in. Temp. of sunk Therm. 76.5 Extreme Temperature of Air observed 58.5 to 80.0 Approximate Mean Temp. of Air deduced 67.8 Diff. between Air and sunk Therm. 8.7 ——————————————————————————- Locality Akbarpore Date Feb. 17 to 19 Elevation 400 feet Depth (2 therm.) 4 ft. 6 in. 5 ft. 6 in. Temp. of sunk Therm. 76.0 Extreme Temperature of Air observed 56.9 to 79.5 Approximate Mean Temp. of Air deduced 68.0 Diff. between Air and sunk Therm. 8.0 ——————————————————————————-

SERIES II.—Himalaya of East Nepal and Sikkim. —————————————————————————————————- Locality Base of Tonglo Date May 19 Elevation 3,000 feet Depth 2 ft. 0 in. Temp. of sunk Therm. 78.0 Extreme Temperature of Air observed 67.5 to 67.0 Approximate Mean Temp. of Air deduced Diff. between Air and sunk Therm. —————————————————————————————————- Locality Simsibong Date May 20 Elevation 7,000 feet Depth 2 ft. 0 in. Temp. of sunk Therm. 61.7 Extreme Temperature of Air observed 59.0 to 59.5 Approximate Mean Temp. of Air deduced Diff. between Air and sunk Therm. —————————————————————————————————- Locality Tonglo saddle Date May 21 to 22 Elevation 10,008 feet Depth 2 ft. 6 in. Temp. of sunk Therm. 50.7* Extreme Temperature of Air observed 47.5 to 57.5 Approximate Mean Temp. of Air deduced 52.5 Diff. between Air and sunk Therm. -1.8 —————————————————————————————————- Locality Tonglo summit Date May 23 Elevation 10,079 feet Depth 2 ft. 6 in. Temp. of sunk Therm. 49.7 Extreme Temperature of Air observed 47.5 to 53.2 Approximate Mean Temp. of Air deduced 52.5 Diff. between Air and sunk Therm. -1.8 —————————————————————————————————- Locality Simonbong Date May 24 Elevation 5,000 feet Depth 2 ft. 6 in. Temp. of sunk Therm. 69.7 Extreme Temperature of Air observed 51.2 to 55.5 Approximate Mean Temp. of Air deduced 52.5 Diff. between Air and sunk Therm. -1.8 —————————————————————————————————- Locality Nanki Date Nov. 4 to 5 Elevation 9,300 feet Depth 3 ft. 0 in. Temp. of sunk Therm. 51.5 Extreme Temperature of Air observed 33.0 to 50.5 Approximate Mean Temp. of Air deduced 41.2 Diff. between Air and sunk Therm. +9.7 —————————————————————————————————- Locality Sakkiazong Date Nov. 9 to 10 Elevation 8,353 feet Depth 3 ft. 0 in. Temp. of sunk Therm. 53.2 Extreme Temperature of Air observed 37.8 to 55.0 Approximate Mean Temp. of Air deduced 46.1 Diff. between Air and sunk Therm. +7.1 —————————————————————————————————- Locality Mywa guola Date Nov. 17 to 18 Elevation 2,132 feet Depth 3 ft. 0 in. Temp. of sunk Therm. 73.0 Extreme Temperature of Air observed 41.0 to 85.0 Approximate Mean Temp. of Air deduced 63.4 Diff. between Air and sunk Therm. +9.6 —————————————————————————————————- Locality Banks of Tambur Date Nov. 18 to 19 Elevation 2,545 feet Depth 3 ft. 0 in. Temp. of sunk Therm. 71.0 Extreme Temperature of Air observed 48.0 to 65.0 Approximate Mean Temp. of Air deduced 55.6 Diff. between Air and sunk Therm. +15.4 —————————————————————————————————- Locality Banks of Tambur higher up river Date Nov. 19 to 20 Elevation 3,201 feet Depth 3 ft. 0 in. Temp. of sunk Therm. 64.5 Extreme Temperature of Air observed 44.3 to 60.0 Approximate Mean Temp. of Air deduced 51.6 Diff. between Air and sunk Therm. +12.9 —————————————————————————————————- Locality Wallanchoon Date Nov. 23 to 25 Elevation 10,386 feet Depth 2 ft. 0 in. Temp. of sunk Therm. 43.5 to 45.0 Extreme Temperature of Air observed 25.0 to 49.7 Approximate Mean Temp. of Air deduced 37.4 Diff. between Air and sunk Therm. +7.6 —————————————————————————————————- Locality Yangma village Date Nov. 30, Dec. 3 Elevation 13,502 feet Depth 2 ft. 0 in. Temp. of sunk Therm. 37.3 to 38.0 Extreme Temperature of Air observed 20.0 to 46.0 Approximate Mean Temp. of Air deduced 33.0 Diff. between Air and sunk Therm. +4.7 —————————————————————————————————- Locality Yangma river Date Dec. 2 to 3 Elevation 10,999 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 41.4 to 42.0 Extreme Temperature of Air observed 23.0 to 40.0 Approximate Mean Temp. of Air deduced 27.9 Diff. between Air and sunk Therm. +3.6 —————————————————————————————————- Locality Bhomsong Date Dec. 24 to 25 Elevation 1,596 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 64.5 to 65.0 Extreme Temperature of Air observed 42.8 to 71.3 Approximate Mean Temp. of Air deduced 57.1 Diff. between Air and sunk Therm. +6.6 —————————————————————————————————- Locality Tchonpong Date Jan. 4 Elevation 4,978 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 55.0 Extreme Temperature of Air observed 33.0 to 54.8 Approximate Mean Temp. of Air deduced 43.9 Diff. between Air and sunk Therm. +11.1 —————————————————————————————————- Locality Jongri Date Jan. 10 to 11 Elevation 13,194 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 34.5 Extreme Temperature of Air observed 3.7 to 34.0 Approximate Mean Temp. of Air deduced 15.3 Diff. between Air and sunk Therm. +19.2 —————————————————————————————————- Locality Buckeem Date Jan. 12 Elevation 8,665 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 43.2 Extreme Temperature of Air observed 40.0 to 29.8 Approximate Mean Temp. of Air deduced 32.4 Diff. between Air and sunk Therm. +10.8 —————————————————————————————————- Locality Choongtam Date May 19 to 25 Elevation 5,268 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 62.5 to 62.7 Extreme Temperature of Air observed 48.0 to 78.3 Approximate Mean Temp. of Air deduced 63.2 Diff. between Air and sunk Therm. -0.6 —————————————————————————————————- Locality Junction of Thlonok and Zemu Date June 13 to 16 Elevation 10,846 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 51.2 Extreme Temperature of Air observed 38.2 to 57.2 Approximate Mean Temp. of Air deduced 49.8 Diff. between Air and sunk Therm. +1.4 —————————————————————————————————- Locality Tungu Date July 26 to 30 Elevation 12,751 feet Depth 2 ft. 5 in. Temp. of sunk Therm. 59.0 to 56.5 Extreme Temperature of Air observed 38.0 to 62.3 Approximate Mean Temp. of Air deduced 50.0 Diff. between Air and sunk Therm. +7.7 —————————————————————————————————- Locality Tungu Date Oct. 10 to 15 Elevation 12,751 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 50.8 to 52.5 Extreme Temperature of Air observed 34.5 to 53.3 Approximate Mean Temp. of Air deduced 41.1 Diff. between Air and sunk Therm. +10.7 —————————————————————————————————- Locality Lamteng Date Aug. 1 to 3 Elevation 8,884 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 62.2 to 62.5 Extreme Temperature of Air observed 47.5 to 78.2 Approximate Mean Temp. of Air deduced 57.0 Diff. between Air and sunk Therm. +5.3 —————————————————————————————————- Locality Choongtam Date Aug. 13 to 15 Elevation 5,268 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 72.1 Extreme Temperature of Air observed 54.8 to 82.0 Approximate Mean Temp. of Air deduced 72.0 Diff. between Air and sunk Therm. +0.1 —————————————————————————————————- Locality Lachoong Date Aug. 17 to 19 Elevation 8,712 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 66.3 to 66.0 Extreme Temperature of Air observed 43.5 to 68.7 Approximate Mean Temp. of Air deduced 57.0 Diff. between Air and sunk Therm. +9.2 —————————————————————————————————- Locality Yeumtong Date Sept. 2 to 8 Elevation 11,919 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 55.5 to 56.1 Extreme Temperature of Air observed 39.5 to 59.5 Approximate Mean Temp. of Air deduced 47.2 Diff. between Air and sunk Therm. +8.6 —————————————————————————————————- Locality Momay Date Sept. 10 to 14 Elevation 15,362 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 52.5 to 51.5 Extreme Temperature of Air observed 31.0 to 62.5 Approximate Mean Temp. of Air deduced 4106 Diff. between Air and sunk Therm. +10.4 —————————————————————————————————- Locality Yeumtso Date Oct. 16 to 18 Elevation 16,8.8 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 43.5 to 43.0 Extreme Temperature of Air observed 4.0 to 52.0 Approximate Mean Temp. of Air deduced 30.6 Diff. between Air and sunk Therm. +12.6 —————————————————————————————————- Locality Lachoong Date Oct. 24 to 25 Elevation 8,712 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 60.2 Extreme Temperature of Air observed 39.0 to 62.6 Approximate Mean Temp. of Air deduced 52.0 Diff. between Air and sunk Therm. +8.2 —————————————————————————————————- Locality Great Rungeet Date Feb. 11 to 13 Elevation 818 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 65.0 Extreme Temperature of Air observed 56.0 to 71.0 Approximate Mean Temp. of Air deduced 63.5 Diff. between Air and sunk Therm. +1.5 —————————————————————————————————- Locality Leebong Date Feb. 14 to 15 Elevation 6,000 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 50.8 to 52.0 Extreme Temperature of Air observed 41.5 to 56.0 Approximate Mean Temp. of Air deduced 46.0 Diff. between Air and sunk Therm. +5.4 —————————————————————————————————- Locality Kursiong Date Apr. 16 Elevation 4,813 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 64.5 Extreme Temperature of Air observed 63.0 to 60.0 Approximate Mean Temp. of Air deduced 63.0 Diff. between Air and sunk Therm. +1.5 —————————————————————————————————- Locality Leebong Date Apr. 22 Elevation 6,000 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 61.8 to 62.0 Extreme Temperature of Air observed 54.0 to 67.8 Approximate Mean Temp. of Air deduced 60.0 Diff. between Air and sunk Therm. +1.9 —————————————————————————————————- Locality Punkabaree Date May 1 Elevation 1,850 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 80.0 Extreme Temperature of Air observed 68.2 to 78.0 Approximate Mean Temp. of Air deduced 76.0 Diff. between Air and sunk Therm. +4.0 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Aug. 15 to 16 Elevation 7,430 feet Depth 5 ft. 0 in. Temp. of sunk Therm. 62.0 to 62.8 Extreme Temperature of Air observed 58.0 to 66.0 Approximate Mean Temp. of Air deduced 61.5 Diff. between Air and sunk Therm. +0.9 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Aug. 15 to 16 Elevation 7,430 feet Depth 7 ft. 7 in. Temp. of sunk Therm. 61.5 to 62.3 Extreme Temperature of Air observed 58.0 to 66.0 Approximate Mean Temp. of Air deduced 61.5 Diff. between Air and sunk Therm. +0.4 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Aug. 20 to 22 Elevation 7,430 feet Depth 5 ft. 0 in. Temp. of sunk Therm. 61.6 to 61.7 Extreme Temperature of Air observed 58.7 to 67.8 Approximate Mean Temp. of Air deduced 61.7 Diff. between Air and sunk Therm. -0.1 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Aug. 20 to 22 Elevation 7,430 feet Depth 7 ft. 7 in. Temp. of sunk Therm. 60.7 Extreme Temperature of Air observed 58.7 to 67.8 Approximate Mean Temp. of Air deduced 61.7 Diff. between Air and sunk Therm. -1.0 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Sept. 9 Elevation 7,430 feet Depth 5 ft. 0 in. Temp. of sunk Therm. 60.2 Extreme Temperature of Air observed 56.2 to 65.0 Approximate Mean Temp. of Air deduced 60.0 Diff. between Air and sunk Therm. +0.2 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Sept. 9 Elevation 7,430 feet Depth 7 ft. 7 in. Temp. of sunk Therm. 60.5 Extreme Temperature of Air observed 56.2 to 65.0 Approximate Mean Temp. of Air deduced 60.0 Diff. between Air and sunk Therm. +0.5 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Oct. 6 Elevation 7,430 feet Depth 7 ft. 7 in. Temp. of sunk Therm. 60.0 Extreme Temperature of Air observed 52.0 to 61.0 Approximate Mean Temp. of Air deduced 58.5 Diff. between Air and sunk Therm. +1.5 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Oct. 20 Elevation 7,430 feet Depth 7 ft. 7 in. Temp. of sunk Therm. 58.5 Extreme Temperature of Air observed 49.7 to 55.2 Approximate Mean Temp. of Air deduced 56.5 Diff. between Air and sunk Therm. +2.0 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date Feb. 18 to 28 Elevation 7,430 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 46.0 to 46.7 Extreme Temperature of Air observed 36.0 to 52.8 Approximate Mean Temp. of Air deduced 43.0 Diff. between Air and sunk Therm. +6.4 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date March 1 to 13 Elevation 7,430 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 46.3 to 48.3 Extreme Temperature of Air observed 34.5 to 53.3 Approximate Mean Temp. of Air deduced 46.0 Diff. between Air and sunk Therm. +1.3 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date April 18 to 20 Elevation 7,430 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 55.3 to 56.0 Extreme Temperature of Air observed 46.0 to 61.3 Approximate Mean Temp. of Air deduced 54.0 Diff. between Air and sunk Therm. +1.7 —————————————————————————————————- Locality Jillapahar (Mr. Hodgson's) Date April 30 Elevation 7,430 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 57.4 Extreme Temperature of Air observed 46.0 to 61.3 Approximate Mean Temp. of Air deduced 55.0 Diff. between Air and sunk Therm. +2.4 —————————————————————————————————- Locality Superintendent's house Date April 21 to 30 Elevation 6,932 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 58.8 to 60.2 Extreme Temperature of Air observed 48.5 to 65.8 Approximate Mean Temp. of Air deduced 58.0 Diff. between Air and sunk Therm. +1.5 —————————————————————————————————- *Sheltered by trees, ground spongy and wet.

SERIES III.—Plains of Bengal —————————————————————————————————- Locality Kishengunj Date May 3 to 4 Elevation 131 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 82.8 to 83.0 (Dry sand) Extreme Temperature of Air observed 70.0 to 85.7 (Dry sand) Approximate Mean Temp. of Air deduced 82.0 Diff. between Air and sunk Therm. +0.8 —————————————————————————————————- Locality Dulalgunj Date May 7 Elevation 130 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 81.3 to 83.0 Extreme Temperature of Air observed 74.3 to 90.3 Approximate Mean Temp. of Air deduced 82.0 Diff. between Air and sunk Therm. -0.7 —————————————————————————————————- Locality Banks of Mahanuddy river Date May 8 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 79.3 to 83.0* Extreme Temperature of Air observed 75.0 to 91.5 Approximate Mean Temp. of Air deduced 83.0 Diff. between Air and sunk Therm. -3.7 —————————————————————————————————- Locality Banks of Mahanuddy river Date May 9 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 87.5 to 83.0* Extreme Temperature of Air observed 77.8 to 92.5 Approximate Mean Temp. of Air deduced 83.0 Diff. between Air and sunk Therm. -4.5 —————————————————————————————————- Locality Banks of Mahanuddy river May 10 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 88.0 to 83.0* Extreme Temperature of Air observed 78.5 to 91.5 Approximate Mean Temp. of Air deduced 82.3 Diff. between Air and sunk Therm. -5.7 —————————————————————————————————- Locality Maldah Date May 11 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 88.8 to 83.0* Extreme Temperature of Air observed 75.3 to 91.3 Approximate Mean Temp. of Air deduced 82.3 Diff. between Air and sunk Therm. -6.5 —————————————————————————————————- Locality Mahanuddy river Date May 14 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 87.8 to 83.0* Extreme Temperature of Air observed 71.0 to 91.7 Approximate Mean Temp. of Air deduced 82.3 Diff. between Air and sunk Therm. -4.5 —————————————————————————————————- Locality Ganges Date May 15 Elevation 100 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 88.0 to 83.0* Extreme Temperature of Air observed 73.0 to 87.8 Approximate Mean Temp. of Air deduced 82.3 Diff. between Air and sunk Therm. -5.7 —————————————————————————————————- Locality Bauleah Date May 16 to 18 Elevation 130 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 87.8 to 89.8 Extreme Temperature of Air observed 78.0 to 106.5 Approximate Mean Temp. of Air deduced 80.5 Diff. between Air and sunk Therm. +7.3 —————————————————————————————————- Locality Dacca Date May 28 to 30 Elevation 72 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 84.9 to 84.3 Extreme Temperature of Air observed 75.3 to 95.5 Approximate Mean Temp. of Air deduced 83.3 Diff. between Air and sunk Therm. +0.9 —————————————————————————————————- * Soil, a moist sand.

SERIES IV.—Khasia Mountains.

—————————————————————————————————- Locality Churra Date June 23 to 25 Elevation 4,226 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 71.8 to 72.3* Extreme Temperature of Air observed 64.8 to 72.2 Approximate Mean Temp. of Air deduced 69.9 Diff. between Air and sunk Therm. +2.2 —————————————————————————————————- Locality Churra Date Oct. 29 to Nov. 16 Elevation 4,226 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 68.3 to 64.0 Extreme Temperature of Air observed 70.7 to 49.3 Approximate Mean Temp. of Air deduced 61.7 Diff. between Air and sunk Therm. +4.5 —————————————————————————————————- Locality Kala-panee Date June 28 to 29 Elevation 5,302 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 69.2 Extreme Temperature of Air observed 64.2 to 71.2 Approximate Mean Temp. of Air deduced 67.2 Diff. between Air and sunk Therm. +2.0 —————————————————————————————————- Locality Kala-panee Date Aug. 5 to 7 Elevation 5,302 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 70.0 to 70.4 Extreme Temperature of Air observed 72.2 to 61.8 Approximate Mean Temp. of Air deduced 64.9 Diff. between Air and sunk Therm. +5.2 —————————————————————————————————- Locality Kala-panee Date Sept. 13 to 14 Elevation 5,302 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 70.2* Extreme Temperature of Air observed 65.5 to 69.8 Approximate Mean Temp. of Air deduced 66.0 Diff. between Air and sunk Therm. +4.2 —————————————————————————————————- Locality Kala-panee Date Oct. 27 to 28 Elevation 5,302 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 66.3* Extreme Temperature of Air observed 64.0 to 56.0 Approximate Mean Temp. of Air deduced 60.0 Diff. between Air and sunk Therm. +6.3 —————————————————————————————————- Locality Moflong Date June 30 to July 4 Elevation 6,062 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 65.0 to 67.3 Extreme Temperature of Air observed 61.0 to 68.3 Approximate Mean Temp. of Air deduced 64.0 Diff. between Air and sunk Therm. +2.2 —————————————————————————————————- Locality Moflong Date July 30 to Aug. 4 Elevation 6,062 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 67.3 Extreme Temperature of Air observed 64.0 to 75.8 Approximate Mean Temp. of Air deduced 68.5 Diff. between Air and sunk Therm. -1.2 —————————————————————————————————- Locality Moflong Date Oct. 25 to 27 Elevation 6,062 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 63.2 Extreme Temperature of Air observed 63.7 to 55.7 Approximate Mean Temp. of Air deduced 64.1 Diff. between Air and sunk Therm. -0.9 —————————————————————————————————- Locality Syong Date July 29 to 30 Elevation 5,725 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 69.2 to 69.3 Extreme Temperature of Air observed 60.0 to 78.5 Approximate Mean Temp. of Air deduced 69.2 Diff. between Air and sunk Therm. +0.1 —————————————————————————————————- Locality Syong Date Oct. 11 to 12 Elevation 5,725 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 67.0 Extreme Temperature of Air observed 65.7 to 55.5 Approximate Mean Temp. of Air deduced 62.8 Diff. between Air and sunk Therm. +4.2 —————————————————————————————————- Locality Myrung Date July 9 to 10 Elevation 5,647 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 66.2 to 66.3 Extreme Temperature of Air observed 60.0 to 73.8 Approximate Mean Temp. of Air deduced 67.5 Diff. between Air and sunk Therm. -1.2 —————————————————————————————————- Locality Myrung Date July 26 to 29 Elevation 5,647 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 68.3 Extreme Temperature of Air observed 78.0 to 64.2 Approximate Mean Temp. of Air deduced 71.1 Diff. between Air and sunk Therm. -2.8 —————————————————————————————————- Locality Myrung Date Oct. 12 to 17 Elevation 5,647 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 66.0 to 64.8 Extreme Temperature of Air observed 70.0 to 55.5 Approximate Mean Temp. of Air deduced 63.0 Diff. between Air and sunk Therm. +2.4 —————————————————————————————————- Locality Myrung Date Oct. 21 to 25 Elevation 5,647 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 64.8 to 64.0 Extreme Temperature of Air observed 66.0 to 53.0 Approximate Mean Temp. of Air deduced 60.5 Diff. between Air and sunk Therm. +3.9 —————————————————————————————————- Locality Nunklow Date July 11 to 26 Elevation 4,688 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 70.5 to 71.3 Extreme Temperature of Air observed 65.5 to 81.5 Approximate Mean Temp. of Air deduced 71.5 Diff. between Air and sunk Therm. -0.5 —————————————————————————————————- Locality Nunklow Date Oct. 17 to 21 Elevation 4,688 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 68.8 to 68.3 Extreme Temperature of Air observed 75.7 to 58.0 Approximate Mean Temp. of Air deduced 6601 Diff. between Air and sunk Therm. +2.5 —————————————————————————————————- Locality Pomrang Date Sept. 15 to 23 Elevation 5,143 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 70.3 to 68.5 Extreme Temperature of Air observed 73.0 to 57.0 Approximate Mean Temp. of Air deduced 65.5 Diff. between Air and sunk Therm. +3.9 —————————————————————————————————- Locality Pomrang Date Oct. 6 to 10 Elevation 5,143 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 68.3 Extreme Temperature of Air observed 73.7 to 58.2 Approximate Mean Temp. of Air deduced 65.0 Diff. between Air and sunk Therm. +3.3 —————————————————————————————————- * Hole full of rain-water.

SERIES V.—Jheels, Gangetic Delta, and Chittagong. —————————————————————————————————- Locality Silchar Date Nov.27 to 30 Elevation 116 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 77.7 to 75.8 Extreme Temperature of Air observed 55.0 to 81.7 Approximate Mean Temp. of Air deduced 69.1 Diff. between Air and sunk Therm. +7.7 —————————————————————————————————- Locality Silhet Date Dec. 3 to 7 Elevation 133 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 73.5 to 73.7 Extreme Temperature of Air observed 63.0 to 74.5 Approximate Mean Temp. of Air deduced 69.5 Diff. between Air and sunk Therm. +3.1 —————————————————————————————————- Locality Noacolly Date Dec. 18 to 19 Elevation 20 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 73.3 Extreme Temperature of Air observed 58.5 to 76.5 Approximate Mean Temp. of Air deduced 69.5 Diff. between Air and sunk Therm. +3.8 —————————————————————————————————- Locality Chittagong Date Dec. 23 to 31 Elevation 191 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 72.5 to 73.0 Extreme Temperature of Air observed 53.2 to 75.0 Approximate Mean Temp. of Air deduced 63.8 Diff. between Air and sunk Therm. +9.0 —————————————————————————————————- Locality Chittagong Date Jan. 14 to 16 Elevation 116 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 73.3 to 73.7 Extreme Temperature of Air observed 61.3 to 78.7 Approximate Mean Temp. of Air deduced 65.5 Diff. between Air and sunk Therm. +8.3 —————————————————————————————————- Locality Chittagong flagstaf hill Date Dec. 28 to 30 Elevation 151 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 72.0 to 71.8 Extreme Temperature of Air observed 55.2 to 74.2 Approximate Mean Temp. of Air deduced 65.3 Diff. between Air and sunk Therm. +6.6 —————————————————————————————————- Locality Hat-hazaree Date Jan.4 to 5 Elevation 20 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 71.3 Extreme Temperature of Air observed 50.5 to 62.0 Approximate Mean Temp. of Air deduced 65.0 Diff. between Air and sunk Therm. +6.3 —————————————————————————————————- Locality Sidhee Date Jan.5 to 6 Elevation 20 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 71.0 Extreme Temperature of Air observed 52.7 to 70.2 Approximate Mean Temp. of Air deduced 65.0 Diff. between Air and sunk Therm. +6.0 —————————————————————————————————- Locality Hattiah Date Jan.6 to 9 Elevation 20 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 67.7 (shaded by trees) Extreme Temperature of Air observed 50.2 to 77.5 Approximate Mean Temp. of Air deduced 64.5 Diff. between Air and sunk Therm. +3.2 —————————————————————————————————- Locality Seetakoond Date Jan. 9 to 14 Elevation 20 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 73.3 to 73.7 Extreme Temperature of Air observed 55.2 to 79.5 Approximate Mean Temp. of Air deduced 70.2 Diff. between Air and sunk Therm. +3.3 —————————————————————————————————- Locality Calcutta* Date Jan. 16 to Feb. 5 Elevation 18 feet Depth 2 ft. 7 in. Temp. of sunk Therm. 76.0 to 77.0 Extreme Temperature of Air observed 56.5 to 82.0** Approximate Mean Temp. of Air deduced 69.3 Diff. between Air and sunk Therm. +7.2 —————————————————————————————————- * Observations at the Mint, etc., by Mr. Muller. ** Observations for temperature of air, taken at the Observatory.



APPENDIX I.

ON THE DECREMENT OF TEMPERATURE IN ASCENDING THE SIKKIM HIMALAYA MOUNTAINS AND KHASIA MOUNTAINS.

I have selected as many of my observations for temperature of the sir as appeared to be trustworthy, and which, also, were taken contemporaneously with others at Calcutta, and I have compared them with the Calcutta observations, in order to find the ratio of decrement of heat to an increase of elevation. The results of several sets of observations are grouped together, but show so great an amount of discrepancy, that it is evident that a long series of months and the selection of several stations are necessary in a mountain country to arrive at any accurate results. Even at the stations where the most numerous and the most trustworthy observations were recorded, the results of different months differ extremely; and with regard to the other stations, where few observations were taken, each one is affected differently from another at the same level with it, by the presence or proximity of forest, by exposure to the east or west, to ascending or descending currents in the valleys, and to cloud or sunshine. Other and still more important modifying influences are to be traced to the monthly variations in the amount of humidity in the air and the strength of its currents, to radiation, and to the evolution of heat which accompanies condensation raising the temperature of elevated regions during the rainy season. The proximity of large masses of snow has not the influence I should have expected in lowering the temperature of the surrounding atmosphere, partly no doubt because of the more rapid condensation of vapours which it effects, and partly because of the free circulation of the currents around it. The difference between the temperatures of adjacent grassy and naked or rocky spots, on the other hand, is very great indeed, the former soon becoming powerfully heated in lofty regions where the sun's rays pass through a rarefied atmosphere, and the rocks especially radiating much of the heat thus accumulated, for long after sunset. In various parts of my journals I have alluded to other disturbing causes, which being all more or leas familiar to meteorologists, I need not recapitulate here. Their combined effects raise all the summer temperatures above what they should theoretically be.

In taking Calcutta as a standard of comparison, I have been guided by two circumstances; first, the necessity of selecting a spot where observations were regularly and accurately made; and secondly, the being able to satisfy myself by a comparison of my instruments that the results should be so far strictly comparable.

I have allowed 1 degree Fahr. for every degree in latitude intervening between Sikkim and Calcutta, as the probable ratio of diminution of temperature. So far as my observations made in east Bengal and in various parts of the Gangetic delta afford a means of solving this question, this is a near approximation to the truth. The spring observations however which I have made at the foot of the Sikkim Himalaya would indicate a much more rapid decrement; the mean temperature of Titalya and other parts of the plains south of the forests, between March and May being certainly 6 degrees-9 degrees lower than Calcutta: this period however is marked by north-west and north-east winds, and by a strong haze which prevents the sun's rays from impinging on the soil with any effect. During the southerly winds, the same region is probably hotter than Calcutta, there being but scanty vegetation, and the rain-fall being moderate.

In the following observations solitary readings are always rejected.

I.—Summer or Rainy Season observations at Dorjiling.

Observations taken during the rainy season of 1848, at Mr. Hodgson's (Jillapahar, Dorjiling) alt. 7,430 feet, exposure free to the north east and west, the slopes all round covered with heavy timber; much mist hence hangs over the station. The mean temperatures of the month at Jillapahar are deduced from horary observations, and those of Calcutta from the mean of the daily maximum and minimum.

No. of Obs. Temp. Equiv. of Month at Jillapahar Temp. Calcutta 1 degree F. ——————————————————————————————- July 284 61.7 86.6 364 feet August 378 61.7 85.7 346 feet September 407 58.9 84.7 348 feet October 255 55.3 83.3 316 feet ——————————————————————————————- 1,324 Mean 344 feet

IL—Winter or dry season observatians at Dorjiling.

1. Observations taken at Mr. J. Muller's, and chiefly by himself, at "the Dale;" elev. 6,956 feet; a sheltered spot, with no forest near, and a free west exposure. 103 observations. Months: November, December, January, and February 1 degree=313 ft. 2. Observations at Dr. Campbell's (Superintendent's) house in April; elev. 6,950 feet; similar exposure to the last. 13 observations in April 1 degree=308 ft. 3. Observations by Mr. Muller at Colinton; elev. 7,179 feet; free exposure to north-west; much forest about the station, and a high ridge to east and south. 38 observations in winter months 1 degree=290 ft. 4. Miscellaneous (11) observations at Leebong; elev. 6000 feet; in February; free exposure all round 1 degree=266 ft. 5. Miscellaneous observations at "Smith's Hotel;" Dorjiling, on a cleared ridge; exposed all round; elev. 6,863 feet. April and May 1 degree=252 ft. ————————- Mean of winter observations 1 degree=286 ft. Mean of summer observations 1 degree=344 ft. ————————- Mean 310 ft.

III.—Miscellaneous observations taken at different places in Dorjiling, elevations 6,900 to 7,400 feet, with the differences of temperature between Calcutta and Dorjiling.

Number Difference Equivalent Month of Observ. of Temperature 1 degree F.= ——————————————————————————————- January 27 30.4 287 ft. February 84 32.8 265 March 37 41.9 196 April 7 36.0 236 March and April 29 37.3 224 July 83 23.6 389 August 74 22.4 415 September 95 25.7 350 October 18 29.5 297 ——————————————————————————————- Sum 454 Mean 31.1 Mean 296 ft.

These, it will be seen, give a result which approximates to that of the sets I and II. Being deduced from observations at different exposures, the effects of these may be supposed to be eliminated. It is to be observed that the probable results of the addition of November and December's observations, would be balanced by those of May and June, which are hot moist months.

IV.—Miscellaneous cold weather observations made at various elevations between 1000 and 17,000 feet, during my journey into east Nepal and Sikkim, in November to January 1848 and 1849. The equivalent to 1 degree Fahr. was deduced from the mean of all the observations at each station, and these being arranged in sets corresponding to their elevations, gave the following results.

Number of Number of Equivalent Elevation Stations Observations 1 degree F.= ———————————————————————————————- 1,000 to 4,000 ft. 27 111 215 ft. 4,000 to 8,000 ft. 52 197 315 8,000 to 12,000 ft. 20 84 327 12,000 to 17,000 ft. 14 54 377 ———————————————————————————————- Sum 113 Sum 446 Mean 308 ft.

The total number of comparative observations taken during that journey, amounted to 563, and the mean equivalent was 1 degree=303 feet, but I rejected many of the observations that were obviously unworthy of confidence.

V.—Miscellaneous observations (chiefly during the rainy season) taken during my journey into Sikkim and the frontier of Tibet, between May 2nd and December 25th, 1848. The observations were reduced as in the previous instance. The rains on this occasion were unusually protracted, and cannot be said to have ceased till mid-winter, which partly accounts for the very high temperatures.

Number of Number of Equivalent Elevation Stations Observations 1 degree F.= ———————————————————————————————- 1,000 to 4,000 ft. 10 45 422 ft. 4,000 to 8,000 ft. 21 283 336 8,000 to 12,000 ft. 18 343 355 12,000 to 17,000 ft. 29 219 417 ———————————————————————————————- Sum 78 Sum 890 Mean 383 ft.

The great elevation of the temperature in the lowest elevations is accounted for by the heating of the valleys wherein these observations were taken, and especially of the rocks on their floors. The increase with the elevation, of the three succeeding sets, arises from the fact that the loftier regions are far within the mountain region, and are less forest clad and more sunny than the outer Himalaya.

A considerable number of observations were taken during this journey at night, when none are recorded at Calcutta, but which are comparable with contemporaneous observations taken by Mr. Muller at Dorjiling. These being all taken during the three most rainy months, when the temperature varies but very little during the whole twenty-four hours, I expected satisfactory results, but they proved very irregular and anomalous.