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,OOQ 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 obaervatians 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 (chiefy 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.
The means were--
At 21 stations of greater elevation than Dorjiling 1 degree=348 ft.
At 17 stations lower in elevation 1 degree=447 ft.
VI.--_Sixty-four contemporaneous observations at Jillapahar, 7,430 feet, and the bed of the Great Rungeet river, 818 feet; taken in
January and February, give 1 degree=322 feet.
VII.--_Observations taken by burying a thermometer two and a half to
three feet deep, in a brass tube, at Dorjiling and at various
elevations near that station._
Month February and March
Upper Stations Jillapahar, 7,430 feet
Lower Stations Leebong, 6000 feet
1 degree= 269 feet
Month February
Upper Stations Jillapahar, 7,430 feet
Lower Stations Guard-house, Great Rungeet, 1,864 feet
1 degree= 298 feet
Month April
Upper Stations Leebong, 6000 feet
Lower Stations Guard-house, Great Rungeet, 1,864 feet
1 degree= 297 feet
Month April
Upper Stations Jillapahar, 7,430 feet
Lower Stations Khersiong, 4,813 feet
1 degree= 297 feet
Month March and April
Upper Stations Khersiong, 4,813 feet
Lower Stations Punkabaree, 1,850 feet
1 degree= 223 feet
Month March, April, May
Upper Stations Jillapahar, 7,430 feet
Lower Stations Punkabaree, 1,850 feet
1 degree= 253 feet
Mean 1 degree=273 feet
The above results would seem to indicate that up to an elevation
of 7,500 feet, the temperature diminishes rather more than 1 degree
Fahr. for every 300 feet of ascent or thereabouts; that this
decrement is much leas in the summer than in the winter months; and I
may add that it is less by day than by night. There is much
discrepancy between the results obtained at greater or less
elevations than 7000 feet; but a careful study of these, which I have
arranged in every possible way, leads me to the conclusion that the
proportion map be roughly indicated thus:--
1 degree=300 feet, for elevations from 1000 to 8000 feet.
1 degree=320 feet, for elevations from 8000 to 10,000 feet.
1 degree=350 feet, for elevations from 10,000 to 14,000 feet.
1 degree=400 feet, for elevations from 14,000 to 18,000 feet.
VIII.--_Khasia mountain observations._
Churra Poonji
Date June 13 to 26
Calcutta Observations 86.3 degrees
Number of Observations 63
Churra Observations 70.1 degrees
Number of Observations 67
1 degree= 300 feet
Altitude above the Sea 4,069 feet
Date August 7 to September 4
Calcutta Observations 84.6 degrees
Number of Observations 196
Churra Observations 69.2 degrees
Number of Observations 214
1 degree= 331 feet
Altitude above the Sea 4,225 feet
Date October 29 to November 16
Calcutta Observations 80.7 degrees
Number of Observations 85
Churra Observations 63.1 degrees
Number of Observations 133
1 degree= 282 feet
Altitude above the Sea 4,225 feet
Total Calcutta Observations 354
Total Churra Observations 414
Mean 1 degree= 304 feet
Kala-panee
Date June, Aug., Sept.
Calcutta Observations 85.5 degrees
Number of Observations 35
Khasia Observations 67.4 degrees
Number of Observations 35
1 degree= 345 feet
Altitude above the Sea 5,302 feet
Moflong
Date June, July, Aug., Oct.
Calcutta Observations 85.9 degrees
Number of Observations 73
Khasia Observations 68.8 degrees
Number of Observations 74
1 degree= 373 feet
Altitude above the Sea 6,062 feet
Syong
Date
Calcutta Observations 85.1 degrees
Number of Observations 4
Khasia Observations 65.0 degrees
Number of Observations 6
1 degree= 332 feet
Altitude above the Sea 5,734 feet
Myrung
Date August
Calcutta Observations 89.1 degrees
Number of Observations 42
Khasia Observations 69.7 degrees
Number of Observations 41
1 degree= 343 feet
Altitude above the Sea 5,632 feet
Myrung
Date October
Calcutta Observations 82.9 degrees
Number of Observations 21
Khasia Observations 63.2 degrees
Number of Observations 58
1 degree= 336 feet
Altitude above the Sea 5,632 feet
Nunklow
Calcutta Observations 86.4 degrees
Number of Observations 139
Khasia Observations 70.9 degrees
Number of Observations 139
1 degree= 372 feet
Altitude above the Sea 4,688 feet
Mooshye
Date September 23
Calcutta Observations 78.5 degrees
Number of Observations 9
Khasia Observations 66.3 degrees
Number of Observations 12
1 degree= 499 feet
Altitude above the Sea 4,863 feet
Pomrang
Date September 23
Calcutta Observations 82.7 degrees
Number of Observations 51
Khasia Observations 65.8 degrees
Number of Observations 51
1 degree= 369 feet
Altitude above the Sea 5,143 feet
Amwee
Date September 23
Calcutta Observations 79.9 degrees
Number of Observations 15
Khasia Observations 67.1 degrees
Number of Observations 11
1 degree= 396 feet
Altitude above the Sea 4,105 feet
Joowy
Date September 23
Calcutta Observations 79.5 degrees
Number of Observations 11
Khasia Observations 69.0 degrees
Number of Observations 7
1 degree= 567 feet
Altitude above the Sea 4,387 feet
Total Calcutta Observations 400
Total Khasia Observations 434
Mean 1 degree= 385 feet
The equivalent thus deduced is far greater than that brought out by
the Sikkim observations. It indicates a considerably higher
temperature of the atmosphere, and is probably attributable to the
evolution of heat during extraordinary rain-fall, and to the
formation of the surface, which is a very undulating table-land, and
everywhere traversed by broad deep valleys, with very steep, often
precipitous flanks; these get heated by the powerful sun, and from
them, powerful currents ascend. The scanty covering of herbage too
over a great amount of the surface, and the consequent radiation of
heat from the earth, must have a sensible influence on the mean
temperature of the summer months.
APPENDIX J.
ON THE MEASUREMENT OF ALTITUDES BY THE BOILING-POINT THERMOMETER.
The use of the boiling-point thermometer for the determination of
elevations in mountainous countries appearing to me to be much
underrated, I have collected the observations which I was enabled to
take, and compared their results with barometrical ones.
I had always three boiling-point thermometers in use, and for several
months five; the instruments were constructed by Newman, Dollond,
Troughton, and Simms, and Jones, and though all in one sense good
instruments, differed much from one another, and from the truth.
Mr. Welsh has had the kindness to compare the three best instruments
with the standards at the Kew Observatory at various temperatures
between 180 degrees and the boiling-point; from which comparison it
appears, that an error of l.5 degrees may be found at some parts of
the scale of instruments most confidently vouched for by admirable
makers. Dollond's thermometer, which Dr. Thomson had used throughout
his extensive west Tibetan journeys, deviated but little from the
truth at all ordinary temperatures. All were so far good, that the
errors, which were almost entirely attributable to carelessness in
the adjustments, were constant, or increased at a constant ratio
throughout all parts of the scale; so that the results of the
different instruments have, after correction, proved strictly
comparable.
The kettle used was a copper one, supplied by Newman, with free
escape for the steam; it answered perfectly for all but very high
elevations indeed, where, from the water boiling at very low
temperatures, the metal of the kettle, and consequently of the
thermometer, often got heated above the temperature of the
boiling water.
I found that no confidence could be placed in observations taken at
great elevations, by plunging the thermometer in open vessels of
boiling water, however large or deep, the abstraction of heat from
the surface being so rapid, that the water, though boiling below, and
hence bubbling above, is not uniformly of the same temperature
throughout.
In the Himalaya I invariably used distilled, or snow or rain-water;
but often as I have tried common river-water for comparison, I never
found that it made any difference in the temperature of the
boiling-point. Even the mineral-spring water at Yeumtong, and the
detritus-charged glacial streams, gave no difference, and I am hence
satisfied that no objection can be urged against river waters of
ordinary purity.
On several occasions I found anomalous rises and falls in the column
of mercury, for which I could not account, except theoretically, by
assuming breaks in the column, which I failed to detect on lifting
the instrument out of the water; at other times, I observed that the
column remained for several minutes stationary, below the true
temperature of the boiling water, and then suddenly rose to it.
These are no doubt instrumental defects, which I only mention as
being sources of error against which the observer must be on the
watch: they can only be guarded against by the use of two
instruments.
With regard to the formula employed for deducing the altitude from a
boiling-point observation, the same corrections are to a great extent
necessary as with barometric observations: if no account is taken of
the probable state of atmospheric pressure at the level of the sea at
or near the place of observation, for the hour of the day and month
of the year, or for the latitude, it is obvious that errors of 600 to
1000 feet may be accumulated. I have elsewhere stated that the
pressure at Calcutta varies nearly one inch (1000 feet), between July
and January; that the daily tide amounts to one-tenth of an inch
(=100 feet); that the multiplier for temperature is too great in the
hot season and too small in the cold; and I have experimentally
proved that more accuracy is to be obtained in measuring heights in
Sikkim, by assuming the observed Calcutta pressure and temperature to
accord with that of the level of the sea in the latitude of Sikkim,
than by employing a theoretical pressure and temperature for the
lower station.
In the following observations, the tables I used were those printed
by Lieutenant-Colonel Boileau for the East India Company's Magnetic
Observatory at Simla, which are based upon Regnault's Table of the
'Elastic Force of Vapour.' The mean height of the barometrical column
is assumed (from Bessel's formula) to be 29.924 at temp. 32 degrees,
in lat. 45 degrees, which, differing only .002 from the barometric
height corresponding to 212 degrees Fahrenheit, as determined
experimentally by Regnault, gives 29.921 as the pressure
corresponding to 212 degrees at the level of the sea.
The approximate height in feet corresponding to each degree of the
boiling-point, is derived from Oltmann's tables. The multipliers for
the mean temperature of the strata of atmosphere passed through, are
computed for every degree Fahrenheit, by the formula for expansion
usually employed, and given in Baily's Astronomical Tables and Biot's
Astronomie Physique.