Volume 2 — APPENDIX F.

ON THE CLIMATE OF SIKKIM.

The meteorology of Sikkim, as of every part of the Himalayan range, is a subject of growing interest and importance; as it becomes yearly more necessary for the Government to afford increased facilities for a residence in the mountains to Europeans in search of health, or of a salubrious climate for their families, or for themselves on retirement from the exhausting service of the plains. I was therefore surprised to find no further register of the weather at Dorjiling, than an insufficient one of the rain-fall, kept by the medical officer in charge of the station; who, in this, as in all similar cases,* [The government of India has gone to an immense expense, and entailed a heavy duty upon its stationary medical officers, in supplying them with sometimes admirable, but more often very inaccurate, meteorological instruments, and requiring that daily registers be made, and transmitted to Calcutta. In no case have I found it to be in the officer's power to carry out this object; he has never time, seldom the necessary knowledge and experience, and far too often no inclination. The majority of the observations are in most cases left to personal native or other servants, and the laborious results I have examined are too frequently worthless.] has neither the time nor the opportunity to give even the minimum of required attention to the subject of meteorology. This defect has been in a measure remedied by Dr. Chapman, who kept a twelve-months' register in 1837, with instruments carefully compared with Calcutta standards by the late James Prinsep, Esq., one of the most accomplished men in literature and science that India ever saw.

The annual means of temperature, rain-fall, etc., vary greatly in the Himalaya; and apparently slight local causes produce such great differences of temperature and humidity, that one year's observations taken at one spot, however full and accurate they may be, are insufficient: this is remarkably the case in Sikkim, where the rainfall is great, and where the difference between those of two consecutive years is often greater than the whole annual London fall. My own meteorological observations necessarily form but a broken series, but they were made with the best instruments, and with a view to obtaining results that should be comparable inter se, and with those of Calcutta; when away from Dorjiling too, in the interior of Sikkim, I had the advantage of Mr. Muller's services in taking observations at hours agreed upon previous to my leaving, and these were of the greatest importance, both for calculating elevations, and for ascertaining the differences of temperature, humidity, diurnal atmospheric tide, and rain-fall; all of which vary with the elevation, and the distance from the plains of India.

Mr. Hodgson's house proved a most favourable spot for an observatory, being placed on the top of the Dorjiling spur, with its broad verandah facing the north, in which I protected the instruments from radiation* [This is a most important point, generally wholly neglected in India, where I have usually seen the thermometer hung in good shade, but exposed to reflected heat from walls, gravel walks, or dry earth. I am accustomed from experience to view all extreme temperatures with great suspicion, on this and other accounts. It is very seldom that the temperature of the free shaded air rises much above 100 degrees, except during hot winds, when the lower stratum only of atmosphere (often loaded with hot particles of sand), sweeps over the surface of a soil scorched by the direct rays of the sun.] and wind. Broad grass-plots and a gravel walk surrounded the house, and large trees were scattered about; on three sides the ground sloped away, while to the north the spur gently rose behind.

Throughout the greater part of the year the prevailing wind is from the south-east, and comes laden with moisture from the Bay of Bengal: it rises at sunrise, and its vapours are early condensed on the forests of Sinchul; billowy clouds rapidly succeed small patches of vapour, which rolling over to the north side of the mountain, are carried north-west, over a broad intervening valley, to Dorjiling. There they bank on the east side of the spur, and this being partially clear of wood, the accumulation is slow, and always first upon the clumps of trees. Very generally by 9 a.m., the whole eastern sky, from the top of Dorjiling ridge, is enveloped in a dense fog, while the whole western exposure enjoys sunshine for an hour or two later. At 7 or 8 a.m., very small patches are seen to collect on Tonglo, which gradually dilate and coalesce, but do not shroud the mountain for some hours, generally not before 11 a.m. or noon. Before that time, however, masses of mist have been rolling over Dorjiling ridge to the westward, and gradually filling up the valleys, so that by noon, or 1 p.m., every object is in cloud. Towards sunset it falls calm, when the mist rises, first from Sinchul, or if a south-east wind sets in, from Tonglo first.

The temperature is more uuiform at Mr. Hodgson's bungalow, which is on the top of the Dorjiling ridge, than on either of its flanks; this is very much because a good deal of wood is left upon it, whose cool foliage attracts and condenses the mists. Its mean temperature is lower by nearly 22 degrees than that of Mr. Muller's and Dr. Campbell's houses, both situated on the slopes, 400 feet below. This I ascertained by numerous comparative observations of the temperature of the air, and by burying thermometers in the earth it is chiefly to be accounted for by the more frequent sunshine at the lower stations, the power of the sun often raising the thermometer in shade to 80 degrees, at Mr. Muller's; whereas during the summer I spent at Mr. Hodgson's it never rose much above 70 degrees, attaining that height very seldom and for a very short period only. The nights, again, are uniformly and equally cloudy at both stations, so that there is no corresponding cold of nocturnal radiation to reduce the temperature.

The mean decrease of temperature due to elevation, I have stated (Appendix I.) to be about 1 degree for every 300 feet of ascent; according to which law Mr. Hodgson's should not be more than 1.5 degrees° colder than Mr. Muller's. These facts prove how difficult it is to choose unexceptionable sites for meteorological observatories in mountainous countries; discrepancies of so great an amount being due to local causes, which, as in this case, are perhaps transient; for should the top of the spur be wholly cleared of timber, its temperature would be materially raised; at the expense, probably, of a deficiency of water at certain seasons. Great inequalities of temperature are also produced by ascending currents of heated air from the Great Rungeet valley, which affect certain parts of the station only; and these raise the thermometer 10 degrees (even when the sun is clouded) above what it indicates at other places of equal elevation.

The mean temperature of Dorjiling (elev. 7,430 feet) is very nearly 50 degrees, or 2 degrees higher than that of London, and 26 degrees below that of Calcutta (78 degrees,* [Prinsep, in As. Soc. Journ., Jan. 1832, p. 30.] or 78.5 degrees in the latest published tables* [Daniell's Met. Essays, vol. ii. p. 341.]); which, allowing 1 degree of diminution of temperature for every degree of latitude leaves 1 degree due to every 300 feet of ascent above Calcutta to the height of Dorjiling, agreeably to my own observations. This diminution is not the same for greater heights, as I shall have occasion to show in a separate chapter of this Appendix, on the decrement of heat with elevation.

A remarkable uniformity of temperature prevails throughout the year at Dorjiling, there being only 22 degrees difference between the mean temperatures of the hottest and coldest months; whilst in London, with a lower mean temperature, the equivalent difference is 27 degrees. At 11,000 feet this difference is equal to that of London. In more elevated regions, it is still greater, the climate becoming excessive at 15,000 feet, where the difference amounts to 30 degrees at least.* [This is contrary to the conclusions of all meteorologists who have studied the climate of the Alps, and is entirely due to the local disturbances which I have so often dwelt upon, and principally to the unequal distribution of moisture in the loftier rearward regions, and the aridity of Tibet. Professor James Forbes states (Ed. Phil. Trans., v. xiv. p. 489):—1. That the decrement of temperature with altitude is most rapid in summer: this (as I shall hereafter show) is not the case in the Himalaya, chiefly because the warm south moist wind then prevails. 2. That the annual range of temperature diminishes with the elevation: this, too, is not the case in Sikkim, because of the barer surface and more cloudless skies of the rearward loftier regions. 3. That the diurnal range of temperature diminishes with the height: that this is not the cane follows from the same cause. 4. That radiation is least in winter: this is negatived by the influence of the summer rains.] The accompanying table is the result of an attempt to approximate to the mean temperatures and ranges of the thermometer at various elevations.

Altitude 11,000 feet 15,000 feet 19,000 feet Mean shade 40.9 29.8 19.8 Mean warmest month 50.0 40.0 32.0 Mean coldest month 24.0 11.0 0.0 Mean daily range of temperature 20.0 27.0 35.0 Rain-fall in inches 40.0 20.0 10.0 1 degree equals 320 feet 350 feet 400 feet

Supposing the same formula to apply (which I exceedingly doubt) to heights above 19,000 feet, 2 degrees would be the mean annual temperature of the summit of Kinchinjunga, altitude 28,178 feet, the loftiest known spot on the globe: this is a degree or two higher than the temperature of the poles of greatest cold on the earth's surface, and about the temperature of Spitzbergen and Melville island.

The upper limit of phenogamic vegetation coincides with a mean temperature of 30 degrees on the south flank of Kinchinjunga, and of 22 degrees in Tibet; in both cases annuals and perennial-rooted herbaceous plants are to be found at elevations corresponding to these mean temperatures, and often at higher elevations in sheltered localities. I have assumed the decrease of temperature for a corresponding amount of elevation to be gradually less in ascending (1 degree=320 feet at 6000 to 10,000 feet, 1 degree=400 feet at 14,000 to 18,000 feet). My observations appear to prove this, but I do not regard them as conclusive; supposing them to be so, I attribute it to a combination of various causes, especially to the increased elevation and yet unsnowed condition of the mass of land elevated above 16,000 feet, and consequent radiation of heat; also to the greater amount of sunshine there; and to the less dense mists which obstruct the sun's rays at all elevations. In corroboration of this I may mention that the decrease of temperature with elevation is much less in summer than in winter, 1 degree of Fahr. being equivalent to only 250 feet in January between 7000 and 13,000 feet, and to upwards of 400 feet in July. Again, at Dorjiling (7,430 feet) the temperature hardly ever rises above 70 degrees in the summer months, yet it often rises even higher in Tibet at 12,000 to 14,000 feet. On the other hand, the winters, and the winter nights especially, are disproportionately cold at great heights, the thermometer falling upwards of 40 degrees below the Dorjiling temperature at an elevation only 6000 feet higher.

The diurnal distribution of temperature is equally and similarly affected by the presence of vapour at different altitudes. The lower and outer ranges of 6000 to 10,000 feet, first receive the diurnal charge of vapour-loaded southerly winds; those beyond them get more of the sun's rays, and the rearward ones more still. Though the summer days of the northern localities are warmer than their elevation would indicate, the nights are not proportionally cold; for the light mist of 14,000 feet, which replaces the dense fog of 7000 feet, effectually obstructs nocturnal radiation, though it is less an obstacle to solar radiation. Clear nights, be it observed, are as rare at Momay (15,300 feet) as at Dorjiling, the nights if windy being rainy; or, if calm, cold currents descend from the mountains, condensing the moist vapours of the valleys, whose narrow floors are at sunrise bathed in mist at all elevations in Sikkim. The rise and dispersion of these dense mists, and their collection and recondensation on the mountains in the morning, is one of the most magnificent phenomena of the Himalaya, when viewed from a proper elevation; it commences as soon as the sun appears on the horizon.

The mean daily range of the thermometer at 7000 feet is 13 degrees in cleared spots, but considerably less in wooded, and certainly one-third less in the forest itself. At Calcutta, which has almost an insular climate, it amounts to 17 degrees; at Delhi, which has a continental one, to 24.6 degrees; and in London to 17.5 degrees. At 11,000 feet it amounts to about 20 degrees, and at 15,000 feet to 27 degrees. These values vary widely in the different months, being much less in the summer or rainy months. The following is probably a fair approximation:—

At 7,000 feet it amounts to 8-9 degrees in Aug. and Sept., and 17 degrees in Dec. At 11,000 feet it amounts to 12 degrees in Aug. and Sept., and 30 degrees in Dec. At 15,000 feet it amounts to 15 degrees in Aug. and Sept., and 40 degrees in Dec. At London it amounts to 20 degrees in Aug. and Sept., and 10 degrees in Dec.

The distribution of temperature throughout the day and year varies less at Dorjiling than in most mountainous countries, owing to the prevailing moisture, the effect of which is analogous to that of a circumambient ocean to an island: the difference being, that in the case of the island the bulk of water maintains an uniform temperature; in that of Dorjiling the quantity of vapour acts directly by interfering with terrestrial and solar-radiation, and indirectly by nurturing a luxuriant vegetation. The result in the latter case is a climate remarkable for its equability, and similar in many features to that of New Zealand, South-west Chili, Fuegia, and the damp west coasts of Scotland and Ireland, and other countries exposed to moist sea winds.

The mean temperature of the year at Dorjiling, as taken by maxima and minima thermometers* [The mean of several of the months, thus deduced, often varies a good deal from the truth, owing to the unequal diurnal distribution of heat; a very few minutes' sunshine raises the temperature l0 degrees or 15 degrees above the mean of the day; which excessive heat (usually transient) the maximum thermometer registers, and consequently gives too high a mean.] by Dr. Chapman, is nearly the same as that of March and October: January, the coldest month, is more than 13.4 degrees colder than the mean of the year; but the hottest month is only 8.3 degrees warmer than the same mean: at Calcutta the months vary less from the mean; at Delhi more; and in London the distribution is wholly different; there being no rains to modify the summer heat, July is 13 degrees hotter, and January 14 degrees colder than the mean of the year.

This distribution of the seasons has a most important effect upon vegetation, to which sufficient attention has not been paid by cultivators of alpine Indian plants; in the first place, though English winters are cold enough for such, the summers are too hot and dry; and, in the second place, the great accession of temperature, causing the buds to burst in spring, occurs in the Himalaya in March, when the temperature at 7000 feet rises 8 degrees above that of February, raising the radiating thermometer always above the freezing point, whence the young leaves are never injured by night frost: in England the corresponding rise is only 3 degrees, and there is no such accession of temperature till May, which is 8 degrees warmer than April; hence, the young foliage of many Himalayan plants is cut off by night frosts in English gardens early in the season, of which Abies Webbiana is a conspicuous example.

The greatest heat of the day occurs at Dorjiling about noon, owing to the prevalent cloud, especially during the rainy months, when the sun shines only in the mornings, if at all, and the clouds accumulate as the day advances. According to hourly observations of my own, it occurred in July at noon, in August at 1 p.m., and in September (the most rainy month) there was only four-tenths of a degree difference between the means of noon, 1 p.m., and 2 p.m., but I must refer to the abstracts at the end of this chapter for evidence of this, and of the wonderful uniformity of temperature during the rainy months. In the drier season again, after September, the greatest heat occurs between 2 and 3 p.m.; in Calcutta the hottest hour is about 2.45 p.m., throughout the year; and in England also about 3 p.m.

The hour whose temperature coincides with the mean of the day necessarily varies with the distribution of cloud and sunshine; it is usually about 7 a.m. and 7 p.m.; whereas in Calcutta the same coincidence occurs at a little before 10 a.m., and in England at about 8 a.m.

Next to the temperature of the air, observations on that of the earth are perhaps of the greatest value; both from their application to horticulture, and from the approximation they afford to the mean temperature of the week or month in which they are taken. These form the subject of a separate chapter.

Nocturnal and solar radiation, the one causing the formation of dew and hoar-frost when the air in the shade is above freezing, end killing plants by the rapid abstraction of heat from all their surfaces which are exposed to the clear sky, and the other scorching the skin and tender plants during the day, are now familiar phenomena, and particularly engaged my attention during my whole Indian journey. Two phenomena particularly obstruct radiation in Sikkim—the clouds and fog from the end of May till October, and the haze from February till May. Two months alone are usually clear; one before and one after the rains, when the air, though still humid, is transparent. The haze has never been fully explained, though a well-known phenomenon. On the plains of India, at the foot of the hills, it begins generally in the forenoon of the cold season, with the rise of the west wind; and, in February especially, obscures the sun's disc by noon; frequently it lasts throughout the twenty-four hours, and is usually accompanied by great dryness of the atmosphere. It gradually diminishes in ascending, and have never experienced it at 10,000 feet; at 7000, however, it very often, in April, obscures the snowy ranges 30 miles off, which are bright and defined at sunrise, and either pale away, or become of a lurid yellow-red, according to the density of this haze, till they disappear at 10 a.m. I believe it always accompanies a south-west wind (which is a deflected current of the north-west) and dry atmosphere in Sikkim.

The observations for solar radiation were taken with a black-bulb thermometer, and also with actinometers, but the value of the data afforded by the latter not being fixed or comparative, I shall give the results in a separate section. (See Appendix K.) From a multitude of desultory observations, I conclude that at 7,400 feet, 125.7 degrees, or + 67 degrees above the temperature of the air, is the average maximum effect of the sun's rays on a black-bulb thermometer* [From the mean of very many observations, I find that 10 degrees is the average difference at the level of the sea, in India, between two similar thermometers, with spherical bulbs (half-inch diam.), the one of black, and the other of plain glass, and both being equally exposed to the sun's rays.] throughout the year, amounting rarely to + 70 degrees and + 80 degrees in the summer months, but more frequently in the winter or spring. These results, though greatly above what are obtained at Calcutta, are not much, if at all, above what may be observed on the plains of India. This effect is much increased with the elevation. At 10,000 feet in December, at 9 a.m., I saw the mercury mount to 132 degrees with a difl: of + 94 degrees, whilst the temperature of shaded snow hard by was 22 degrees; at 13,100 feet, in January, at 9 a.m., it has stood at 98 degrees, diff. + 68.2 degrees; and at 10 a.m., at 114 degrees, diff. + 81.4 degrees, whilst the radiating thermometer on the snow had fallen at sunrise to 0.7 degree. In December, at 13,500 feet, I have seen it 110 degrees, diff. + 84 degrees; at 11 a.m., 11,500 feet; 122 degrees, diff: + 82 degrees. This is but a small selection from many instances of the extraordinary power of solar radiation in the coldest months, at great elevations.

Nocturnal and terrestrial radiation are even more difficult phenomena for the traveller to estimate than solar radiation, the danger of exposing instruments at night being always great in wild countries. I most frequently used a thermometer graduated on the glass, and placed in the focus of a parabolic reflector, and a similar one laid upon white cotton,* [Snow radiates the most powerfully of any substance I have tried; in one instance, at 13,000 feet, in January, the thermometer on snow fell to 0.2 degree, which was 10.8 degrees below the temperature at the time, the grass showing 6.7 degrees; and on another occasion to l.2 degrees, when the air at the time (before sunrise) was 21.2 degrees; the difference therefore being 20 degrees. I have frequently made this observation, and always with a similar result; it may account for the great injury plants sustain from a thin covering of ice on their foliage, even when the temperature is but little below the freezing-point.] and found no material difference in the mean of many observations of each, though often 1 degree to 2 degrees in individual ones. Avoiding radiation from surrounding objects is very difficult, especially in wooded countries. I have also tried the radiating power of grass and the earth; the temperature of the latter is generally less, and that of the former greater, than the thermometer exposed on cotton or in the reflector, but much depends on the surface of the herbage and soil.

The power of terrestrial, like that of solar radiation, increases with the elevation, but not in an equal proportion. At 7,400 feet, the mean of all my observations shows a temperature of 35.4 degrees. During the rains, 3 degrees to 4 degrees is the mean maximum, but the nights being almost invariably cloudy, it is scarcely on one night out of six that there is any radiation. From October to December the amount is greater = 10 degrees to 12, and from January till May greater still, being as much as 15 degrees. During the winter months the effect of radiation is often felt throughout the clear days, dew forming abundantly at 4000 to 8000 feet in the shaded bottoms of narrow valleys, into which the sun does not penetrate till 10 a.m., and from which it disappears at 3 p.m. I have seen the thermometer in the reflector fall 12 degrees at 10 a.m. in a shaded valley. This often produces an anomalous effect, causing the temperature in the shade to fall after sunrise; for the mists which condense in the bottom of the valleys after midnight disperse after sunrise, but long before reached by the sun, and powerful radiation ensues, lowering the surrounding temperature: a fall of 1 degree to 2 degrees after sunrise of air in the shade is hence common in valleys in November and December.* [Such is the explanation which I have offered of this phenomenon in the Hort. Soc. Journal. On thinking over the matter since, I have speculated upon the probability of this fall of temperature being due to the absorption of heat that must become latent on the dispersion of the dense masses of white fog that choke the valleys at sunrise.] The excessive radiation of the winter months often gives rise to a curious phenomenon; it causes the formation of copious dew on the blanket of the traveller's bed, which radiates heat to the tent roof, and this inside either an open or a closed tent. I have experienced this at various elevations, from 6000 to 16,000 feet. Whether the minimum temperature be as high as 50 degrees, or but little above zero, the effect is the same, except that hoar-frost or ice forms in the latter case. Another remarkable effect of nocturnal radiation is the curl of the alpine rhododendron leaves in November, which is probably due to the freezing and consequent expansion of the water in the upper strata of cells exposed to the sky. The first curl is generally repaired by the ensuing day's sun, but after two or three nights the leaves become permanently curled, and remain so till they fall in the following spring.

I have said that the nocturnal radiation in the English spring months is the great obstacle to the cultivation of many Himalayan plants; but it is not therefore to be inferred that there is no similar amount of radiation in the Himalaya; for, on the contrary, in April its amount is much greater than in England, frequently equalling 13 degrees of difference; and I have seen 16 degrees at 7,500 feet; but the minimum temperature at the time is 51 degrees, and the absolute amount of cold therefore immaterial. The mean minimum of London is 38 degrees, and, when lowered 5.5 degrees by radiation, the consequent cold is very considerable. Mr. Daniell, in his admirable essay on the climate of London, mentions 17 degrees as the maximum effect of nocturnal radiation ever observed by him. I have registered 16 degrees in April at Dorjiling; nearly as much at 6000 feet in February; twice 13 degrees, and once 14.2 degrees in September at 15,500 feet; and 10 degrees in October at 16,800 feet; nearly 13 degrees in January at 7000 feet; 14.5 degrees in February at that elevation, and, on several occasions, 14.7 degrees at 10,000 feet in November.

The annual rain-fall at Dorjiling averages 120 inches (or 10 feet), but varies from 100 to 130 in different years; this is fully three times the amount of the average English fall,* [The general ideas on the subject of the English rain-fall are so very vague, that I may be pardoned for reminding my readers that in 1852, the year of extraordinary rain, the amounts varied from 28.5 inches in Essex, to 50 inches at Cirencester, and 67.5 (average of five years) at Plympton St. Mary's, and 102.5 at Holme, on the Dart.] and yet not one-fourth of what is experienced on the Khasia hills in Eastern Bengal, where fifty feet of rain falls. The greater proportion descends between June and September, as much as thirty inches sometimes falling in one month. From November to February inclusive, the months are comparatively dry; March and October are characterised by violent storms at the equinoxes, with thunder, destructive lightning, and hail.

The rain-gauge takes no account of the enormous deposition from mists and fogs: these keep the atmosphere in a state of moisture, the amount of which I have estimated at 0.88 as the saturation-point at Dorjiling, 0.83 being that of London. In July, the dampest month, the saturation-point is 0.97; and in December, owing to the dryness of the air on the neighbouring plains of India, whence dry blasts pass over Sikkim, the mean saturation-point of the month sometimes falls as low as 0.69.

The dew-point is on the average of the year 49.3 degrees, or 3 degrees below the mean temperature of the air. In the dampest month (July) the mean dew-point is only eight-tenths of a degree below the temperature, whilst in December it sinks 10 degrees below it. In London the dew-point is on the average 5.6 degrees below the temperature; none of the English months are so wet as those of Sikkim, but none are so dry as the Sikkim December sometimes is.

On the weight of the atmosphere in Sikkim; and its effects on the human frame.

Of all the phenomena of climate, the weight of the atmosphere is the most remarkable for its elusion of direct observation, when unaided by instruments. At the level of the sea, a man of ordinary bulk and stature is pressed upon by a auperincumbent weight of 30,000 pounds or 13.5 tons. An inch fall or rise in the barometer shows that this load is lightened or increased, sometimes in a few hours, by nearly 1,000 pounds; and no notice is taken of it, except by the meteorologist, or by the speculative physician, seeking the subtle causes of epidemic and endemic domplaints. At Dorjiling (7,400 feet), this load is reduced to less than 2,500 pounds, with no appreciable result whatever on the frame, however suddenly it be transported to that elevation. And the observation of my own habits convinced me that I took the same amount of meat, drink, sleep, exercise and work, not only without inconvenience, but without the slightest perception of my altered circumstances. On ascending to 14,000 feet, owing to the diminished supply of oxygen, exercise brings on vertigo and headache; ascending higher still, lassitude and tension across the forehead ensue, with retching, and a sense of weight dragging down the stomach, probably due to dilatation of the air contained in that organ. Such are the all but invariable effects of high elevations; varying with most persons according to the suddenness and steepness of the ascent, the amount and duration of exertion, and the length of time previously passed at great heights. After having lived for some weeks at 15,300 feet, I have thence ascended several times to 18,500, and once above 19,000 feet, without any sensations but lassitude and quickness of pulse;* [I have in a note to vol. ii. chapter xxiii, stated that I never experienced in my own person, nor saw in others, bleeding at the ears, nose, lips, or eyelids.] but in these instances it required great caution to avoid painful symptoms. Residing at 15,300 feet, however, my functions were wholly undisturbed; nor could I detect any quickness of pulse or of respiration when the body was at rest, below 17,000 feet. At that elevation, after resting a party of eight men for an hour, the average of their and my pulses was above 100 degrees, both before and after eating; in one case it was 120 degrees, in none below 80 degrees.

Not only is the frame of a transient visitor unaffected (when at rest) by the pressure being reduced from 30,000 to 13,000 pounds, but the Tibetan, born and constantly residing at upwards of 14,000 feet, differs in no respect that can be attributed to diminished pressure, from the native of the level of the sea. The averaged duration of life, and the amount of food and exercise is the same; eighty years are rarely reached by either. The Tibetan too, however inured to cold and great elevations, still suffers when he crosses passes 18,000 or 19,000 feet high, and apparently neither more nor less than I did.

Liebig remarks (in his "Animal Chemistry") that in an equal number of respirations,* [For the following note I am indebted to my friend, C. Muller, Esq., of Patna.—

According to Sir H. Davy, a man consumes 45,504 cubic inches of oxygen in twenty-four hours, necessitating the inspiration of 147,520 cubic inches of atmospheric air.—At pressure 23 inches, and temp. 60 degrees this volume of atmospheric air (dry) would weigh 35,138•75 grains.-At pressure 30 in., temp. 80°, it would weigh 43,997.83 gr.

The amount of oxygen in atmospheric air is 23.32 per cent. by weight. The oxygen, then, in 147,520 cubic inches of dry air, at pressure 23 in., temp. 80 degrees, weighs 8,194.35 gr.; and at pressure 30 in., temp. 80 degrees, it weighs 10,260.25 gr.

Hence the absolute quantity of oxygen in a given volume of atmospheric air, when the pressure is 23 in., and the temp. 60 degrees, is 20.14 per cent. less than when the pressure is 30 in. and the temp. 80 degrees.

When the air at pressure 23 in:, temp. 60 degrees, is saturated with moisture, the proportion of dry air and aqueous vapour in 100 cubic inches is as follows:— Dry air 97.173 Vapour 2.827 At pressure 30 in., temp. 80 degrees, the proportions are:— Dry air 96.133 Vapour 3.867

The effect of aqueous vapour in the sir on the amount of oxygen available for consumption, is very trifling; and it must not be forgotten that aqueous vapour supplies oxygen to the system as well as atmospheric air.] we consume a larger amount of oxygen at the level of the sea than on a mountain; and it can be shown that under ordinary circumstances at Dorjiling, 20.14 per cent. less is inhaled than on the plains of India. Yet the chest cannot expand so as to inspire more at once, nor is the respiration appreciably quickened; by either of which means nature would be enabled to make up the deficiency. It is true that it is difficult to count one's own respirations, but the average is considered in a healthy man to be eighteen in a minute; in my own case it is sixteen, an acceleration of which by three or four could not have been overlooked, in the repeated trials I made at Dorjiling, and still less the eight additional inhalations required at 15,000 feet to make up for the deficiency of oxygen in the air of that elevation.

It has long been surmised that an alpine vegetation may owe some of its peculiarities to the diminished atmospheric pressure; and that the latter being a condition which the gardener cannot supply, he can never successfully cultivate such plants in general. I know of no foundation for this hypothesis; many plants, natives of the level of the sea in other parts of the world, and some even of the hot plains of Bengal, ascend to 12,000 and even 15,000 feet on the Himalaya, unaffected by the diminished pressure. Any number of species from low countries may be cultivated, and some have been for ages, at 10,000 to 14,000 feet without change. It is the same with the lower animals; innumerable instances may with ease be adduced of pressure alone inducing no appreciable change, whilst there is absence of proof to the contrary. The phenomena that accompany diminished pressure are the real obstacles to the cultivation of alpine plants, of which cold and the excessive climate are perhaps the most formidable. Plants that grow in localities marked by sudden extremes of heat and cold, are always very variable in stature, habit, and foliage. In a state of nature we say the plants "accommodate themselves" to these changes, and so they do within certain limits; but for one that survives of all the seeds that germinate in these inhospitable localities, thousands die. In our gardens we can neither imitate the conditions of an alpine climate, nor offer others suited to the plants of such climates.

The mean height of the barometer at Mr. Hodgson's was 23.010, but varied 0.161 between July, when it was lowest, and October, when it was highest; following the monthly rise and fall of Calcutta as to period, but not as to amount (or amplitude); for the mercury at Calcutta stands in July upwards of half an inch (0.555 Prinsep) lower than it does in December.

The diurnal tide of atmosphere is as constant as to the time of its ebb and flow at Dorjiling as at Calcutta; and a number of very careful observations (made with special reference to this object) between the level of the plains of India, and 17,000 feet, would indicate that there is no very material deviation from this at any elevation in Sikkim. These times are very nearly 9.50 a.m. and about 10 p.m. for the maxima, the 9.50 a.m. very constantly, and the 10 p.m. with more uncertainty; and 4 a.m. and 4 p.m. for the minima, the afternoon ebb being most true to its time, except during the rains.

At 9.50 a.m. the barometer is at its highest, and falls till 4 p.m., when it stands on the average of the year 0.074 of an inch lower; during the same period the Calcutta fall is upwards of one-tenth of an inch (0.121 Prinsep).

It has been proved that at considerable elevations in Europe, the hours of periodic ebb and flow differ materially from those which prevail at the level of the sea; but this is certainly not the case in the Sikkim Himalaya.

The amplitude decreases in amount from 0.100 at the foot of the hills, to 0.074 at 7,000 feet; and the mean of 132 selected unexceptionable observations, taken at nine stations between 8000 and 15,500 feet, at 9.50 a.m. and 4 p.m., gives an average fall of 0.056 of an inch; a result which is confirmed by interpolation from numerous horary observations at these and many other elevations, where I could observe at the critical hours.

That the Calcutta amplitude is not exceptionally great, is shewn by the register kept at different places in the Gangetic valley and plains of India, between Saharunpore and the Bay of Bengal. I have seen apparently trustworthy records of seven* [Calcutta, Berampore, Benares, Nagpore, Moozufferpore, Delhi, and Saharunpore.] such, and find that in all it amounts to between 0.084 and 0.120 inch, the mean of the whole being 0.101 of an inch.

The amplitude is greatest (0.088) in the spring months (March, April, and May), both at Dorjiling and Calcutta: it is least at both in June and July, (0.027 at Dorjiling), and rises again in autumn (to .082 in September).

The horary oscillations also are as remarkably uniform at all elevations, as the period of ebb and flow: the mercury falls slowly from 9.50 a.m. (when it is at its highest) till noon, then rapidly till 3 p.m., and slowly again till 4 p.m.; after which there is little change until sunset; it rises rapidly between 7 and 9 p.m., and a little more till 10 p.m.; thence till 4 a.m. the fall is inconsiderable, and the great rise occurs between 7 and 9 a.m.

It is well known that these fluctuations of the barometer are due to the expansion and contraction by heat and moisture of the column of atmosphere that presses on the mercury, in the cistern of the instrument: were the air dry, the effect would be a single rise and fall;* [This law, for which we are indebted to Professor Dove, has been clearly explained by Colonel Sabine in the appendix to his translation of Humboldt's "Cosmos," vol. i. p. 457.] the barometer would stand highest at the hottest of the twenty-four hours, and lowest at the coldest; and such is the case in arid continental regions which are perennially dry. That such would also be the case at Calcutta and throughout the Himalaya of Sikkim, is theoretically self-evident, and proved by my horary observations taken during the rainy months of 1848. An inspection of these at the end of this section (where a column contains the pressure of dry air) shows but one maximum of pressure, which occurs at the coldest time of the twenty-four hours (early in the morning), and one minimum in the afternoon. In the table of mean temperatures of the months, also appended to this section, will also be found a column allowing the pressure of dry air, whence it will be seen that there is but one maximum of the pressure of dry air, occurring at the coldest season in December, and one minimum, in July. The effect of the vapour is the same on the annual as upon the diurnal march of the pressure, producing a double maximum and minimum in the year in one case, and in the twenty-four hours in the other.

I append a meteorological register of the separate months, but at the same time must remind the reader that it does not pretend to strict accuracy. It is founded upon observations made at Dorjiling by Dr. Chapman in the year 1837, for pressure temperature and wet-bulb only; the other data and some modifications of the above are supplied from observations of my own. Those for terrestrial and nocturnal radiation are accurate as far as they go, that is to say, they are absolute temperatures taken by myself, which may, I believe, be recorded in any year, but much higher are no doubt often to be obtained. The dew-points and saturations are generally calculated from the mean of two day observations (10 a.m. and 4 p.m.) of the wet-bulb thermometer, together with the minimum, or are taken from observations of Daniell's hygrometer; and as I find the mean of the temperature of 10 a.m., 4 p.m., and the minimum, to coincide within a few tenths with the mean temperature of the whole day, I assume that the mean of the wet-bulb observations of the same hours will give a near approach to that of the twenty-four hours. The climate of Dorjiling station has been in some degree altered by extensive clearances of forest, which render it more variable, more exposed to night frosts and strong sun-heat, and to drought, the drying up of small streams being one direct consequence. My own observations were taken at Mr. Hodgson's house, elevated 7,430 feet, the position of which I have indicated at the commencement of this section, where the differences of climate due to local causes are sufficiently indicated to show that in no two spots could similar meteorological results be obtained. At Mr. Hodgson's, for instance, the uniformity of temperature and humidity is infinitely more remarkable than at Dr. Chapman's, possibly from my guarding more effectually against radiation, and from the greater forests about Mr. Hodgson's house. I have not, however, ventured to interfere with the temperature columns on this account.

DORJILING METEOROLOGICAL REGISTER.

Jan. Feb. Mar. Apr. May June Pressure of Atmosphere* 23.307 .305 .307 .280 .259 .207 Range of Pressure .072 .061 .083 .085 .088 .067 Mean Shade 40.0 42.1 50.7 55.9 57.6 61.2 Max. Shade 56.0 57.0 66.5 68.5 69.0 71.0 Max. Sun 119.0 124.0 120.0 125.0 125.0 126.2 Greatest Diff. 72.0 78.0 60.0 66.0 65.0 62.2 Mean Max. Shade 47.2 50.0 58.4 63.7 65.3 66.7 Minim. Shade 29.0 25.5 37.0 38.0 38.0 51.5 Minim. Rad. 16.0 23.0 27.8 33.0 40.0 47.0 Greatest Diff. 12.7 15.3 8.7 16.0 10.0 4.8 Mean Minim. Shade 32.8 34.2 43.1 48.1 50.0 55.8 Mean Daily Range of Temp. 14.4 15.8 15.3 15.6 15.3 10.9 Sunk Therm. 46.0 48.0 50.0 58.0 61.0 62.0 Mean Dew-Point 34.3 37.2 45.8 49.8 54.4 59.5 Mean Dryness 5.1 3.9 5.8 6.6 2.7 2.0 Force of Vapour .216 .239 .323 .371 .434 .515 Pressure of Dry Air 23.091 .066 .084 22.909 .825 .692 Mean Saturation .84 .87 .82 .80 .91 .93 Rain in Inches 1.72 0.92 1.12 2.52 9.25 26.96

July Aug. Sep. Oct. Nov. Dec. Mean Pressure of Atmosphere* 23.203 .230 .300 .372 .330 .365 23.289 Range of Pressure .062 .070 .082 .075 .078 .062 .074 Mean Shade 61.4 61.7 59.9 58.0 50.0 43.0 53.5 Max. Shade 69.5 70.0 70.0 68.0 63.0 56.0 65.4 Max. Sun 130.0 133.0 142.0 133.0 123.0 108.0 125.7 Greatest Diff. 62.0 62.0 70.0 65.0 68.0 77.2 67.3 Mean Max. Shade 65.5 66.1 64.7 66.5 56.5 51.6 60.2 Minim. Shade 56.0 54.5 51.5 43.5 38.0 32.5 41.3 Minim. Rad. 52.0 50.0 47.5 32.0 30.0 26.0 35.4 Greatest Diff. 3.5 3.5 10.0 12.0 12.0 10.0 9.9 Mean Minim. Shade 57.3 57.4 55.2 49.5 43.5 34.9 46.8 Mean Daily Range of Temp. 8.2 8.7 9.5 17.0 13.0 16.7 13.4 Sunk Therm. 62.2 62.0 61.0 60.0 55.0 49.0 56.2 Mean Dew-Point 60.7 60.4 58.5 52.5 46.5 31.8 49.4 Mean Dryness 0.8 1.1 1.4 4.2 3.2 10.6 4.0 Force of Vapour .535 .530 .498 .407 .331 .198 .383 Pressure of Dry Air 22.668 .700 .802 .865 .999 23.165 22.906 Mean Saturation .97 .96 .95 .86 .90 .69 .88 Rain in Inches 25.34 29.45 15.76 8.66 0.11 0.45 Sum 122.26

*These are taken from Dr. Chapman's Table; and present a greater annual range (=0.169) than my observations in 1848-9, taken at Mr. Hodgson's, which is higher than Dr. Chapman's; or Mr. Muller's, which is a little lower, and very near.

Horary Observations at Jillapahar, Dorjiling, Alt. 7,430 feet.

JULY, 1848

No. of Observations 7 23 27 22 20 26 12 11 25 Hour 1 a.m. 8 9 10 11 Noon 1 p.m. 2 3 Barom. corrected 22.877 .882 .884 +.899 .899 .884 .876 .866 .852 Temp. Air 59.6 62.1 62.6 63.5 64.1 65.0 64.1 64.4 64.8 D.P. 58.9 60.6 61.3 61.7 62.3 63.1 61.7 61.0 62.6 Diff. 0.7 1.5 1.3 1.8 1.8 1.9 2.4 3.4 2.2 Tens. of Vapour .504 .534 .546 .554 .565 .580 .566 .541 .571 Weight of Vapour 5.65 6.03 6.10 6.12 6.27 6.44 6.13 6.00 6.32 Humidity .988 .950 .960 .945 .945 .940 .923 .892 .930 Press. of Dry Air 22.373 .348 .338 .345 .334 .304 .310 .325 .281

No. of Observations 23 13 10 6 6 22 6 6 19 Hour 4 p.m. 5 6 7 8 9 10 11 M.n. Barom. corrected 22.846 -.840 .845 .853 .867 .878 .885 +.887 .887 Temp. Air 64.1 64.7 63.7 62.7 61.0 60.7 60.5 60.2 59.8 D.P. 61.7 64.0 61.5 61.1 59.5 59.4 59.5 59.2 59.1 Diff. 2.4 0.7 2.2 1.6 1.5 1.3 1.0 1.0 0.7 Tens. of Vapour .554 .597 .549 .542 .515 .512 .514 .508 .507 Weight of Vapour 6.13 6.62 6.12 6.03 5.74 5.72 5.75 5.70 5.68 Humidity .924 .978 .928 .948 .952 .960 .968 .965 .975 Press. of Dry Air 22.292 -.243 .296 .311 .352 .366 .371 .379 +.382

AUGUST

No. of Observations 15 26 28 28 24 23 21 21 21 Hour 1 a.m. 8 9 10 11 Noon 1 p.m. 2 3 Barom. corrected 22.909 .904 .915 +.917 .915 .905 .898 .884 .873 Temp. Air 59.8 62.1 63.1 64.3 64.7 64.7 65.3 65.0 64.8 D.P. 59.5 61.5 61.9 62.7 63.1 63.4 63.3 63.4 63.1 Diff. 0.3 0.6 1.2 1.6 1.6 1.3 2.0 1.6 1.7 Tens. of Vapour .514 .549 .558 .572 .580 .586 .584 .586 .579 Weight of Vapour 5.70 6.13 6.20 6.35 6.42 6.50 6.48 6.50 6.43 Humidity .992 .980 .962 .950 .948 .958 .940 .950 .943 Press. of Dry Air +22.395 .355 .357 .345 .335 .319 .314 .298 .294

No. of Observations 19 19 19 19 19 19 19 19 19 Hour 4 p.m. 5 6 7 8 9 10 11 M.n. Barom. corrected 22.855 -.853 .863 .865 .878 .890 +.823 .892 .889 Temp. Air 63.9 63.2 62.3 61.6 61.1 60.7 60.3 60.1 60.0 D.P. 62.4 61.7 60.8 60.4 60.2 60.0 59.7 59.7 59.4 Diff. 1.5 1.5 1.5 1.2 0.9 0.7 0.6 0.4 0.6 Tens. of Vapour .568 .554 .538 .531 .527 .523 .518 .517 .513 Weight of Vapour 6.30 6.15 6.00 5.92 5.88 5.85 5.78 5.79 5.73 Humidity .952 .952 .952 .952 .970 .976 .980 .988 .980 Press. of Dry Air -.287 .299 .325 .334 .351 .367 .375 .375 .376

DECEMBER

No. of Observations 28 29 28 24 23 23 23 23 23 Hour 8 a.m. 9 10 11 Noon 1 p.m. 2 3 4 Barom. corrected 23.000 .013 +.018 .009 22.995 .980 .962 .947 -.944 Temp. Air 59.2 60.1 60.8 61.6 62.4 62.7 62.8 62.3 61.8 D.P. 58.1 58.5 59.5 60.0 60.5 60.5 60.4 60.0 59.9 Diff. 1.1 1.6 1.3 1.6 1.9 2.2 2.4 2.3 1.9 Tens. of Vapour .492 .497 .514 .523 .533 .532 .531 .522 .521 Weight of Vapour 5.50 5.57 5.77 5.83 5.93 5.92 5.90 5.83 5.82 Humidity .968 .945 .958 .950 .942 .942 .925 .924 .940 Press. of Dry Air 22.508 .516 .504 .506 .462 .448 .431 .425 -.423

No. of Observations 19 19 20 21 22 24 24 23 Hour 5 p.m. 6 7 8 9 10 11 M.n. Barom. corrected 22.944 .948 .958 .975 .986 +.991 .989 .994 Temp. Air 60.3 59.4 58.7 58.2 57.8 57.4 57.0 56.7 D.P. 58.6 58.4 57.4 57.0 56.6 56.4 55.9 55.4 Diff. 1.7 1.0 1.3 1.2 1.2 1.0 1.1 1.3 Tens. of Vapour .498 .496 .479 .473 .467 .463 .456 .449 Weight of Vapour 5.58 5.58 5.60 5.33 5.25 5.23 5.15 5.07 Humidity .940 .968 .960 .962 .960 .968 .962 .927 Press. of Dry Air .446 .452 .479 .502 .519 .528 .533 +.545

OCTOBER (22 days)

No. of Observations 11 19 20 20 19 13 15 13 13 14 Hour 6-6.30 a.m. 7 8 9 10 11 Noon 1 p.m. 2 3 Barom. corrected 23.066 .072 .086 .099 +.100 .079 .072 .055 .033 .027 Temp. Air 54.4 54.3 55.2 56.3 57.1 57.6 57.9 58.0 57.7 57.9 D.P. 52.7 52.3 53.7 54.4 55.5 55.6 56.1 56.4 56.6 56.2 Diff. 1.7 2.0 1.5 1.9 1.6 2.0 1.8 1.6 1.1 1.7 Tens. of Vapour .4.9 .403 .423 .434 .450 .451 .459 .463 .466 .460 Weight of Vapour 4.65 4.58 4.78 4.90 5.07 5.08 5.15 5.17 5.25 5.16 Humidity .943 .925 .950 .935 .942 .935 .940 .950 .962 .940 Press. of Dry Air +22.657 +.669 .663 .665 .650 .628 .613 .592 .567 .567

No. of Observations 16 13 6 7 3 7 14 18 14 Hour 4 p.m. 5 6 7 8 9 10 11 M.n. Barom. corrected 23.024 -.022 .033 .045 .038 .061 +.072 .067 .068 Temp. Air 57.9 56.6 55.9 55.4 53.7 55.1 54.6 54.5 54.1 D.P. 56.1 54.8 54.4 53.8 53.3 54.1 53.0 53.0 52.8 Diff. 1.8 1.8 1.5 1.6 0.4 1.0 1.6 1.5 1.3 Tens. of Vapour .458 .439 .433 .424 .417 .429 .413 .413 .411 Weight of Vapour 5.15 4.98 4.90 4.80 4.75 4.83 4.82 4.82 4.65 Humidity .940 .948 .950 .950 .990 .965 .949 .950 .962 Press. of Dry Air -.566 .583 .600 .621 .621 .632 .659 .654 .657

APPENDIX G.

ON THE RELATIVE HUMIDITY, AND ABSOLUTE AMOUNT OF VAPOUR CONTAINED IN THE ATMOSPHERE AT DIFFERENT ELEVATIONS IN THE SIKKIM HIMALAYA.

My observations for temperature and wet-bulb being for the most part desultory, taken at different dates, and under very different conditions of exposure, etc., it is obvious that those at one station are hardly, if at all, comparative with those of another, and I have therefore selected only such as were taken at the same date and hour with others taken at the Calcutta Observatory, or as can easily be reduced; which thus afford a standard (however defective in many respects) for a comparison. I need hardly remind my reader that the vapour-charged wind of Sikkim is the southerly one, which blows over Calcutta; that in its passage northwards to Sikkim in the summer months, it traverses the heated plains at the foot of the Himalaya, and ascending that range, it discharges the greater part of its moisture (120 to 140 inches annually) over the outer Himalayan ranges, at elevations of 4000 to 8000 feet. The cooling effect of the uniform covering of forest on the Sikkim ranges is particularly favourable to this deposition, but the slope of the mountains being gradual, the ascending currents are not arrested and cooled so suddenly as in the Khasia mountains, where the discharge is consequently much greater. The heating of the atmosphere, too, over the dry plains at the foot of the outer range, increases farther its capacity for the retention of vapour, and also tends to render the rain-fall less sudden and violent than on the Khasia, where the south wind blows over the cool expanse of the Jheels. It will be seen from the following observations, that in Sikkim the relative humidity of the atmosphere remains pretty constantly very high in the summer months, and at all elevations, except in the rearward valleys; and even there a humid atmosphere prevails up to 14,000 feet, everywhere within the influence of the snowy mountains. The uniformly high temperature which prevails throughout the summer, even at elevations of 17,000 and 18,000 feet, is no doubt proximately due to the evolution of heat during the condensation of these vapours. It will be seen by the pages of my journal, that continued sunshine, and the consequent heating of the soil, is almost unknown during the summer, at any elevation on the outer or southward ranges of Dorjiling: but the sunk thermometer proves that in advancing northward into the heart of the mountains and ascending, the sun's effect is increased, the temperature of the earth becoming in summer considerably higher than that of the air. With regard to the observations themselves, they may be depended upon as comparable with those of Calcutta, the instruments having been carefully compared, and the cases of interpolation being few. The number of observations taken at each station is recorded in a separate column; where only one is thus recorded, it is not to be regarded as a single reading, but the mean, of several taken during an hour or longer period. I have rejected all solitary observations, even when accompanied by others at Calcutta; and sundry that were, for obvious reasons, likely to mislead. Where many observations were taken at one place, I have divided them into sets, corresponding to the hours at which alone the Calcutta temperature and wet-bulb thermometer are recorded,* [Sunrise; 9.50 a.m.; noon; 2.40 p.m.; 4 p.m., and sunset.] in order that meteorologists may apply them to the solution of other questions relating to the distribution of heat and moisture. The Dorjiling observations, and those in the immediate neighbourhood of that station, appeared to me sufficiently numerous to render it worth while classing them in months, and keeping them in a series by themselves. The tensions of vapour are worked from the wet-bulb readings by Apjohn's formula and tables, corrected for the height of the barometer at the time. The observations, except where otherwise noted, are taken by myself.

SERIES I. Observations made at or near Dorjiling.

JANUARY, 1849

DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 15 The Dale* 6956 ft. 9.50 a.m. 42.9 32.4 10.5 .202 15 Mr. Muller's … Noon 45.8 33.8 12.0 .212 10 … … 2.40 p.m. 48.3 37.4 10.9 .241 8 … … 4 p.m. 48.6 37.8 10.8 .244 9 … … Sunset 46.5 37.1 9.4 .238 ——————————————————————————————————- 57 … … Mean 46.4 35.7 10.7 .227 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 15 The Dale* 6956 ft. 9.50 a.m. 67.5 55.3 12.2 .446 15 Mr. Muller's … Noon 72.9 55.7 17.2 .455 10 … … 2.40 p.m. 76.1 55.1 21.0 .444 8 … … 4 p.m. 75.1 54.8 20.3 .440 9 … … Sunset 71.8 54.9 16.9 .441 ——————————————————————————————————- 57 … … Mean 72.7 55.2 17.5 .445 ——————————————————————————————————-

*Observations to which the asterisk is affixed were taken by Mr. Muller.

Dorjiling.—Humidity 0.700 Calcutta 0.562 ,, Vapour in cubic foot of atmosphere 2.63 gr. ,, 4.86 gr.

JANUARY, 1850 DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. Sunrise 32.8 30.1 2.7 .186 6 Mr. Hodgson's … 9.50 a.m. 39.5 34.7 4.8 .219 3 … … Noon 42.4 38.0 4.4 .246 5 … … 2.40 p.m. 41.9 37.8 4.1 .244 5 … … 4 p.m. 41.1 38.5 2.6 .250 5 … … Sunset 38.7 35.6 3.1 .226 13 … … Miscel. 41.9 39.9 2.0 .263 4 Saddle of road 7412 ft. Do. 41.1 36.4 4.7 .233 at Sinchul. 1 Pacheem. 7258 ft. Do. 39.8 38.7 1.1 .252 ——————————————————————————————————- 45 … … Mean 39.9 36.6 3.3 .235 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. Sunrise 51.5 48.5 3.0 .354 6 Mr. Hodgson's … 9.50 a.m. 66.9 55.1 11.8 .444 3 … … Noon 74.1 51.7 22.4 .395 5 … … 2.40 p.m. 78.3 51.4 26.9 .391 5 … … 4 p.m. 77.4 59.5 17.9 .514 5 … … Sunset 72.4 54.7 17.7 .438 13 … … Miscel. 77.9 60.1 17.8 .525 4 Saddle of road 7412 ft. Do. 67.7 57.2 10.5 .476 at Sinchul. 1 Pacheem. 7258 ft. Do. 71.6 50.5 21.2 .379 ——————————————————————————————————- 45 … … Mean 70.9 54.3 16.6 .435 ——————————————————————————————————-

Dorjiling.—Humidity 0.890 Calcutta 0.580 ,, Weight of vapour 2.75 gr. ,, 4.86 gr.

FEBRUARY DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. Sunrise 36.9 34.7 2.2 .219 18 1850 … 9.50 a.m. 42.9 38.6 4.3 .251 12 … … Noon 44.8 41.3 3.5 .276 12 … … 2.40 p.m. 44.8 37.4 7.4 .241 17 … … 4 p.m. 44.0 35.6 8.4 .226 19 … … Sunset 42.4 35.8 6.6 .228 13 The Dale* 6956 ft. Miscel. 40.8 35.1 5.7 .222 ——————————————————————————————————- 97 … … Mean 42.4 36.9 5.4 .238 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. Sunrise 60.0 54.2 5.8 .431 18 1850 … 9.50 a.m. 72.8 58.8 14.0 .503 12 … … Noon 79.8 58.7 21.2 .501 12 … … 2.40 p.m. 82.4 57.9 24.5 .487 17 … … 4 p.m. 81.1 58.1 23.0 .492 19 … … Sunset 76.3 60.7 15.6 .536 13 The Dale* 6956 ft. Miscel. 69.9 59.8 10.1 .518 ——————————————————————————————————- 97 … … Mean 74.6 58.3 16.3 .495 ——————————————————————————————————-

Dorjiling.—Humidity 0.828 Calcutta 0.590 ,, Weight of vapour 2.75 gr. ,, 5.40 gr.

MARCH DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 10 Jillapahar, 7430 ft. 9.50 a.m. 44.2 42.7 1.5 .290 8 1850 … Noon 45.5 43.0 2.5 .293 5 … … 2.40 p.m. 46.4 44.0 2.4 .303 8 … … 4 p.m. 45.5 43.4 2.1 .297 6 … … Sunset 43.1 41.5 1.6 .278 3 Pacheem. 7258 ft. Misc. 44.8 44.6 0.2 .310 ——————————————————————————————————- 40 … … Mean 44.9 43.2 1.7 .295 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 10 Jillapahar, 7430 ft. 9.50 a.m. 81.6 64.1 17.5 .602 8 1850 … Noon 88.2 57.0 31.2 .472 5 … … 2.40 p.m. 91.3 53.2 38.1 .416 8 … … 4 p.m. 90.1 52.0 38.1 .399 6 … … Sunset 82.9 63.7 19.2 .590 3 Pacheem. 7258 ft. Misc. 85.0 74.8 10.2 .848 ——————————————————————————————————- 40 … … Mean 86.5 60.8 25.7 .555 ——————————————————————————————————-

Dorjiling.—Humidity 0.940 Calcutta 0.438 ,, Weight of vapour 3.42 gr. ,, 5.72 gr.

APRIL DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. 9.50 a.m. 57.0 40.2 16.8 .266 3 1849 … Noon 59.8 44.1 15.7 .305 1 … … 2.40 p.m. 60.2 44.4 15.8 .308 7 Dr. Campbell's 6932 ft. 9.50 a.m. 61.8 53.3 8.5 .417 2 1850 … Noon 65.4 52.8 12.6 .411 4 … … 4 p.m. 57.5 53.7 13.8 .423 3 … … Sunset 56.9 51.4 5.5 .392 ——————————————————————————————————- 23 … … Mean 59.8 48.6 11.3 .360 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Jillapahar, 7430 ft. 9.50 a.m. 90.3 71.3 19.0 .758 3 1849 … Noon 97.0 64.5 32.5 .607 1 … … 2.40 p.m. 97.7 73.4 24.3 .812 7 Dr. Campbell's 6932 ft. 9.50 a.m. 86.7 66.3 20.4 .644 2 1850 … Noon 91.3 68.8 22.5 .699 4 … … 4 p.m. 88.6 72.1 16.5 .778 3 … … Sunset 82.8 73.0 9.8 .800 ——————————————————————————————————- 23 … … Mean 90.6 69.9 20.7 .728 ——————————————————————————————————-

Dorjiling.—Humidity 0.684 Calcutta 0.523 ,, Weight of vapour 3.98 gr. ,, 7.65 gr.

MAY DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Smith's Hotel, 6863 ft. Misc. 57.2 55.0 2.2 .443 1848 45 Colinton,* 7179 ft. Misc. 60.4 57.9 12.5 .466 1849 ——————————————————————————————————- 48 … … Mean 58.8 56.5 12.4 .455 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 3 Smith's Hotel, 6863 ft. Misc. 88.6 78.4 10.2 .951 1848 45 Colinton,* 7179 ft. Misc. 90.0 77.2 12.8 .917 1849 ——————————————————————————————————- 48 … … Mean 89.3 77.8 11.5 .934 ——————————————————————————————————-

Dorjiling.—Humidity 0.926 Calcutta 0.698 ,, Weight of vapour 5.22 gr. ,, 9.90 gr.

JUNE DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 40 Colinton* 7179 ft. Misc. 60.9 57.6 13.3 .483 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 40 Colinton* 7179 ft. Misc. 85.5 78.4 7.1 .952 ——————————————————————————————————-

Dorjiling.—Humidity 0.895 Calcutta 0.800 ,, Weight of vapour 5.39 gr. ,, 10.17 gr.

JULY DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 18 Jillapahar, 7430 ft. 9.50 a.m. 63.2 61.4 1.8 .548 25 1848 … Noon 65.0 62.6 2.4 .570 24 … … 2.40 p.m. 64.7 62.3 2.4 .565 16 … … 4 p.m. 63.8 61.5 2.3 .550 31 The Dale,* 6952 ft. 6 a.m. 60.2 58.7 1.5 .537 31 1848 … 2 p.m. 66.3 63.3 3.0 .621 31 … … 6 p.m. 63.0 60.9 2.1 .575 ——————————————————————————————————- 176 … … Mean 63.7 61.5 2.2 .567 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 18 Jillapahar, 7430 ft. 9.50 a.m. 87.0 79.4 7.6 .983 25 1848 … Noon 89.0 80.0 9.0 1.001 24 … … 2.40 p.m. 88.1 79.4 8.7 .983 16 … … 4 p.m. 87.2 79.5 7.7 .985 31 The Dale,* 6952 ft. 6 a.m. 81.3 79.0 2.3 .969 31 1848 … 2 p.m. 88.0 79.6 8.4 .989 31 … … 6 p.m. 84.8 79.2 5.6 .977 ——————————————————————————————————- 176 … … Mean 86.5 79.4 7.0 .984 ——————————————————————————————————-

Dorjiling.—Humidity 0.929 Calcutta 0.800 ,, Weight of vapour 6.06 gr. ,, 10.45 gr.

AUGUST DORJILING No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 23 Jillapahar, 7430 ft. 9.50 a.m. 64.2 62.4 1.8 .567 21 1848 … Noon 64.7 63.3 1.4 .584 17 … … 2.40 p.m. 64.7 62.8 1.9 .574 13 … … 4 p.m. 63.9 62.5 1.4 .568 31 The Dale,* 6952 ft. 6 a.m. 60.5 59.5 1.0 .551 31 1848 … 2 p.m. 65.3 63.6 1.7 .628 31 … … 6 p.m. 62.8 61.8 1.0 .591 ——————————————————————————————————- 167 … … Mean 63.7 62.3 1.5 .580 ——————————————————————————————————-

CALCUTTA No. of Obs. Place Elev. Hour Tp. D.P. Diff. Tens. ——————————————————————————————————- 23 Jillapahar, 7430 ft. 9.50 a.m. 85.8 79.1 6.7 .973 21 1848 … Noon 87.2 79.2 8.0 .976 17 … … 2.40 p.m. 87.4 79.3 8.1 .979 13 … … 4 p.m. 86.5 79.5 7.0 .984 31 The Dale,* 6952 ft. 6 a.m. 80.8 78.8 2.0 .962 31 1848 … 2 p.m. 87.2 79.2 8.0 .976 31 … … 6 p.m. 83.7 78.7 5.0 .959 ——————————————————————————————————- 167 … … Mean 85.5 79.1 6.4 .973 ——————————————————————————————————-

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 Calutta.

HUMIDITY

No. of Diff. Obs. Month Dorjiling Calcutta Dorjiling ————————————————————————————- 102 January -.795 .571 +.224 97 February .828 .590 +.238 40 March .940 -.438 +.502 23 April .684 .523 +.161 48 May .926 .698 +.228 40 June .895 .800 +.095 176 July .929 .800 +.129 167 August +.955 +.818 +.136 185 September .932 .760 +.172 74 October .950 .658 +.292 46 Nov. and Dec. .798 .640 +.158 ————————————————————————————— 998 Mean 0.876 0.663 +.212

WEIGHT OF VAPOUR IN CUBIC FOOT OF AIR

No. of Diff. Obs. Month Dorjiling Calcutta Calcutta ———————————————————————————— 102 January -2.68 -4.80 +2.12 97 February 2.75 5.40 +2.65 40 March 3.42 5.72 +2.30 23 April 3.98 7.65 +3.67 48 May 5.22 9.90 +4.62 40 June 5.39 10.17 +4.78 176 July 6.06 10.05 +3.99 167 August +6.25 +10.35 +4.10 185 September 5.72 9.88 +4.16 74 October 4.74 8.55 +3.81 46 Nov. and Dec. 3.40 6.27 +2.87 ———————————————————————————— 998 Mean 4.51 8.07 +3.55

It is hence evident, from nearly 1,000 comparative observations, that the atmosphere is relatively more humid at Dorjiling than at Calcutta, throughout the year. As the southerly current, to which alone is due all the moisture of Sikkim, traverses 200 miles of land, and discharges from sixty to eighty inches of rain before arriving at Dorjiling, it follows that the whole atmospheric column is relatively drier over the Himalaya than over Calcutta; that the absolute amount of vapour, in short, is less than it would otherwise be at the elevation of Dorjiling, though the relative humidity is so great. A glance at the table at the end of this section appears to confirm this; for it is there shown that, at the base of the Himalaya, at an elevation of only 250 feet higher than Calcutta, the absolute amount of vapour is less, and of relative humidity greater, than at Calcutta.

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