The position and elevation of the perpet_Himalayan Journals — Volume 2 Or, Notes of a Naturalist in Bengal, the Sikkim and Nepal Himalayas, the Khasia Mountains, etc.

as I have asserted in the pages of my Journal, that the limit of

perpetual snow is laid down too low in all mountain regions, and that

accumulations in hollows, and the descent of glacial ice, mask the

phenomenon more effectually than is generally allowed. In this work I

define the limit, as is customary, in general terms only, as being

that where the accumulations are very great, and whence they are

continuous upwards, on gentle slopes. All perpetual snow, however,

becomes ice, and, as such, obeys the laws of glacial motion, moving

as a viscous fluid; whence it follows that the lower edge of a

snow-bed placed on a slope is, in one sense, the termination of a

glacier, and indicates a position below that where all the snow that

falls melts. I am well aware that it is impossible to define the

limit required with any approach to accuracy. Steep and broken

surfaces, with favourable exposures to the sun or moist winds, are

bare much above places where snow lies throughout the year; but the

occurrence of a gentle slope, free of snow, and covered with plants,

cannot but indicate a point below that of perpetual snow. Such is the

case with the "Jardin" on the Mer de Glace, whose elevation is 9,500

feet, whereas that of perpetual snow is considered by Professor J.

Forbes, our best authority, to be 8,500 feet. Though limited in area,

girdled by glaciers, presenting a very gentle slope to the east, and

screened by surrounding mountains from a considerable proportion of

the sun's rays, the Jardin is clear, for fully three months of the

year, of all but sporadic falls of snow, that never lie long; and so

are similar spots placed higher on the neighbouring slopes; which

facts are quite at variance with the supposition that the perpetual

snow-line is below that point in the Mont Blanc Alps. On the Monte

Rosa Alps, again, Dr. Thomson and I gathered plants in flower, above

12,000 feet on the steep face of the Weiss-thor Pass, and at 10,938

feet on the top of St. Theodule; but in the former case the rocks are

too steep for any snow to lie, they are exposed to the south-east,

and overhang a gorge 8000 feet deep, up which no doubt warm currents

ascend; while at St. Theodule the plants were growing on a slope

which, though gentle, is black and stony, and exposed to warm

ascending currents, as on the Weiss-thor; and I do not consider

either of these as evidences of the limit of perpetual snow being

higher than their position.] vary with those of the individual

ranges, and their exposure to the south wind. The expression that the

perpetual snow lies lower and deeper on the southern slopes of the

Himalayan mountains than on the northern, conveys a false impression.

It is better to say that the snow lies deeper and lower on the

southern faces of the individual mountains and spurs that form the

snowy Himalaya. The axis itself of the chain is generally far north

of the position of the spurs that catch all the snow, and has

comparatively very little snow on it, most of what there is lying

upon north exposures.

A reference to the woodcut will show that the same circumstances

which affect the distribution of moisture and vegetation, determine

the position, amount, and duration of the snow. The principal fall

will occur, as before shown, where the meridional range first attains

a sufficiently great elevation, and the air becomes consequently

cooled below 32 degrees; this is at a little above 14,000 feet,

sporadic falls occurring even in summer at that elevation: these,

however, melt immediately, and the copious winter falls also are

dissipated before June. As the depth of rain-fall diminishes in

advancing north to the higher parts of the meridional ranges, so does

that of the snow-fall. The permanence of the snow, again, depends

on--1. The depth of the accumulation; 2. The mean temperature of the

spot; 3. The melting power of the sun's rays; 4. The prevalence and

strength of evaporating winds. Now at 14,000 feet, though the

accumulation is immense, the amount melted by the sun's rays is

trifling, and there are no evaporating winds; but the mean

temperature is so high, and the corroding powers of the rain (which

falls abundantly throughout summer) and of the warm and humid

ascending currents are so great, that the snow is not perennial.

At 15,500 feet, again, it becomes perennial, and its permanence at

this low elevation (at P) is much favoured by the accumulation and

detention of fogs over the rank vegetation which prevails from S

nearly to P; and by the lofty mountains beyond it, which shield it

from the returning dry currents from the north. In proceeding north

all the circumstances that tend to the dispersion of the snow

increase, whilst the fall diminishes. At P the deposition is enormous

and the snow-line low--16,000 feet; whilst at T little falls, and the

limit of perpetual snow is 19,000 and 20,000 feet. Hence the anomaly,

that the snow-line ascends in advancing north to the coldest

Himalayan regions. The position of the greatest peaks and of the

greatest mass of perpetual snow being generally assumed as indicating

a ridge and watershed, travellers, arguing from single mountains

alone, on the meridional ridges, have at one time supported and at

another denied the assertion, that the snow lies longer and deeper on

the north than on the south slope of the Himalayan ridge.

The great accumulation of snow at 15,000 feet, in the parallel of P,

exercises a decided influence on the vegetation. The alpine

rhododendrons hardly reach 14,000 feet in the broad valleys and

round-headed spurs of the mountains of the Tunkra and Chola passes;

whilst the same species ascend to 16,000, and one to 17,000 feet, at

T. Beyond the latter point, again, the great aridity of the climate

prevents their growth, and in Tibet there are generally none even as

low as 12,000 and 14,000 feet. Glaciers, again, descend to 15,000

feet in the tortuous gorges which immediately debouch from the snows

of Kinchinjunga, but no plants grow on the debris they carry down,

nor is there any sward of grass or herbage at their base, the

atmosphere immediately around being chilled by enormous accumulations

of snow, and the summer sun rarely warming the soil. At T, again, the

glaciers do not descend below 16,000 feet, but a greensward of

vegetation creeps up to their bases, dwarf rhododendrons cover the

moraines, and herbs grow on the patches of earth carried down by the

latter, which are thawed by the more frequent sunshine, and by the

radiation of heat from the unsnowed flanks of the valleys down which

these ice-streams pour.

Looking eastward or westward on the map of India, we perceive that

the phenomenon of perpetual snow is regulated by the same laws.

From the longitude of Upper Assam in 95 degrees E to that of Kashmir

in 75 degrees E, the lowest limit of perpetual snow is 15,500 to

16,000 feet, and a shrubby vegetation affects the most humid

localities near it, at 12,000 to 14,000 feet. Receding from the

plains of India and penetrating the mountains, the climate becomes

drier, the snowline rises, and vegetation diminishes, whether the

elevation of the land increases or decreases; plants reaching 17,000

and 18,000 feet, and the snow-line, 20,000 feet. To mention extreme

cases; the snow-level of Sikkim in 27 degrees 30 minutes is at 16,000

feet, whereas in latitude 35 degrees 30 minutes Dr. Thomson found the

snow line 20,000 feet on the mountains near the Karakoram Pass, and

vegetation up to 18,500 feet--features I found to be common also to

Sikkim in latitude 28 degrees.

The Himalaya, north of Nepal, and thence eastward to the bend of the

Yaru-Tsampu (or Tibetan Burrampooter) has for its geographical limits

the plains of India to the south, and the bed of the Yaru to the

north. All between these limits is a mountain mass, to which Tibet

(though so often erroneously called a plain)* [The only true account

of the general features of eastern Tibet is to be found in MM. Huc

and Gabet's travels. Their description agrees with Dr. Thomson's

account of western Tibet, and with my experience of the parts to the

north of Sikkim, and the information I everywhere obtained.

The so-called _plains_ are the flat floors of the valleys, and the

terraces on the margins of the rivers, which all flow between

stupendous mountains. The term "maidan," so often applied to Tibet by

the natives, implies, not a plain like that of India, but simply an

open, dry, treeless country, in contrast to the densely wooded wet

regions of the snowy Himalaya, south of Tibet.] forms no exception.

The waters from the north side of this chain flow into the Tsampu,

and those from the south side into the Burrampooter of Assam, and the

Ganges. The line, however tortuous, dividing the heads of these

waters, is the watershed, and the only guide we have to the axis of

the Himalaya. This has never been crossed by Europeans, except by

Captain Turner's embassy in 1798, and Captain Bogle's in 1779, both

of which reached the Yaru river. In the account published by Captain

Turner, the summit of the watershed is not rigorously defined, and

the boundary, of Tibet and Bhotan is sometimes erroneously taken for

it; the boundary being at that point a southern spur of Chumulari.*

[Between Donkia and Chumulari lies a portion of Tibet (including the

upper part of the course of the Machoo river) bounded on the east by

Bhotan, and on the west by Sikkim (see chapter xxii). Turner, when

crossing the Simonang Pass, descended westwards into the valley of

the Machoo, and was still on the Indian watershed.] Eastwards from

the sources of the Tsampu, the watershed of the Himalaya seems to

follow a very winding course, and to be everywhere to the north of

the snowy peaks seen from the plains of India. It is by a line

through these snowy peaks that the axis of the Himalaya is

represented in all our maps; because they _seem_ from the plains to

be situated on an east and west ridge, instead of being placed on

subsidiary meridional ridges, as explained above. It is also across

or along the subsidiary ridges that the boundary line between the

Tibetan provinces and those of Nepal, Sikkim, and Bhotan, is usually

drawn; because the enormous accumulations of snow form a more

efficient natural barrier than the greater height of the less snowed

central part of the chain beyond them.

Though, however, our maps draw the axis through the snowy peaks,

they also make the rivers to rise beyond the latter, on the northern

slopes as it were, and to flow southwards through gaps in the axis.

Such a feature is only reconcilable with the hypothesis of the chain

being double, as the Cordillera of Peru and Chili is said to be,

geographically, and which in a geological sense it no doubt is: but

to the Cordillera the Himalaya offers no parallel. The results of

Dr. Thomson's study of the north-west Himalaya and Tibet, and

my own of the north-east extreme of Sikkim and Tibet, first gave

me an insight into the true structure of this chain. Donkia mountain

is the culminant point of an immensely elevated mass of mountains, of

greater mean height than a similarly extensive area around Kinchin

junga. It comprises Chumulari, and many other mountains much

above 20,000 feet, though none equalling Kinchinjunga, Junnoo, and

Kubra. The great lakes of Ramchoo and Cholamoo are placed on it; and

the rivers rising on it flow in various directions; the Painomchoo

north-west into the Yaru; the Arun west to Nepal; the Teesta south-

west through Sikkim; the Machoo south, and the Pachoo south-east,

through Bhotan. All these rivers have their sources far beyond the

great snowed mountains, the Arun most conspicuously of all, flowing

completely at the back or north of Kinchinjunga. Those that flow

southwards, break through no chain, nor do they meet any contraction

as they pass the snowy parts of the mountains which bound the valleys

in which they flow, but are bound by uniform ranges of lofty

mountains, which become more snowy as they approach the plains of

India. These valleys, however, gradually contract as they descend,

being less open in Sikkim and Nepal than in Tibet, though there

bounded by rugged mountains, which from being so bare of snow and of

vegetation, do not give the same impression of height as the isolated

sharper peaks which rise out of a dense forest, and on which the snow

limit is 4,000 or 5,000 feet lower.

The fact of the bottom of the river valleys being flatter towards the

watershed, is connected with that of their fall being less rapid at

that part of their course; this is the consequence of the great

extent in breadth of the most elevated portion of the chain. If we

select the Teesta as an example, and measure its fall at three points

of its course, we shall find the results very different. From its

principal source at Lake Cholamoo, it descends from 17,000 to 15,000

feet, with a fall of 60 feet to the mile; from 15,000 to 12,000 feet,

the fall is 140 feet to the mile; in the third part of its course it

descends from 12,000 to 5000 feet, with a fall of 160 feet to the

mile; and in the lower part the descent is from 5000 feet to the

plains of India at 300 feet, giving a fall of 50 feet to the mile.

There is, however, no marked limit to these divisions; its valley.

gradually contracts, and its course gradually becomes more rapid.

It is worthy of notice that the fall is at its maximum through that

part of its valley of which the flanks are the most loaded with snow;

where the old moraines are very conspicuous, and where the present

accumulations from landslips, etc., are the most extensive.* [It is

not my intention to discuss here the geological bearings of this

curious question; but I may state that as the humidity of the climate

of the middle region of the river-course tends to increase the fall

in a given space, so I believe the dryness of the climate of the

loftier country has the opposite effect, by preserving those

accumulations which have raised the floors of the valleys and

rendered them level.]

With reference to Kinchinjunga, these facts are of importance, as

showing that mere elevation is in physical geography of secondary

importance. That lofty mountain rises from a spur of the great range

of Donkia, and is quite removed from the watershed or axis of the

Himalaya, the rivers which drain its northern and southern flanks

alike flowing to the Ganges. Were the Himalaya to be depressed 18,000

feet, Kubra, Junnoo, Pundim, etc., would form a small cluster of

rocky islands 1000 to 7000 feet high, grouped near Kinchinjunga,

itself a cape 10,000 feet high, which would be connected by a low,

marrow neck, with an extensive and mountainous tract of land to its

north-east; the latter being represented by Donkia. To the north of

Kinchin a deep bay or inlet would occupy the present valley of the

Arun, and would be bounded on the north by the axis of the Himalaya,

which would form a continuous tract of land beyond it. Since writing

the above, I have seen Professor J. Forbes's beautiful work on the

glaciers of Norway: it fully justifies a comparison of the Himalaya

to Norway, which has long been a familiar subject of theoretical

enquiry with Dr. Thomson and myself. The deep narrow valleys of

Sikkim admirably represent the Norwegian fiords; the lofty, rugged,

snowy mountains, those more or less submerged islands of the

Norwegian coast; the broad rearward watershed, or axis of the chain,

with its lakes, is the same in both, and the Yaru-tsampu occupies the

relative position of the Baltic.

Along the whole chain of the Himalaya east of Kumaon there are, I

have no doubt, a succession of such lofty masses as Donkia, giving

off stupendous spurs such as that on which Kinchin forms so

conspicuous a feature. In support of this view we find every river

rising far beyond the snowy peaks, which are separated by

continuously unsnowed ranges placed between the great white masses

that these spurs present to the observer from the south.* [At vol. i.

chapter viii, I have particularly called attention to the fact, that

west of Kinchinjunga there is no continuation of a snowy Himalaya, as

it is commonly called. So between Donkia and Chumulari there is no

perpetual snow, and the valley of the Machoo is very broad, open, and

comparatively flat.] From the Khasia mountains (south-east of Sikkim)

many of these groups or spurs were seen by Dr. Thomson and myself, at

various distances (80 to 210 miles); and these groups were between

the courses of the great rivers the Soobansiri, Monass, and Pachoo,

all east of Sikkim. Other masses seen from the Gangetic valley

probably thus mark the relative positions of the Arun, Cosi, Gunduk,

and Gogra rivers.

Another mass like that of Chumulari and Donkia, is that around the

Mansarowar lakes, so ably surveyed by the brothers Captains R. and H.

Strachey, which is evidently the centre of the Himalaya. From it the

Gogra, Sutlej, Indus, and Yaru rivers all flow to the Indian side of

Asia; and from it spring four chains, two of which are better known

than the others. These are:--1. The eastern Himalaya, whose axis runs

north of Nepal, Sikkim, and Bhotan, to the bend of the Yaru, the

valley of which it divides from the plains of India. 2. The

north-west Himalaya, which separates the valley of the Indus from the

plains of India. Behind these, and probably parallel to them, lie two

other chains. 3. The Kouenlun or Karakoram chain, dividing the Indus

from the Yarkand river. 4. The chain north of the Yaru, of which

nothing is known. All the waters from the two first of these chains,

flow into the Indian Ocean, as do those from the south faces of the

third and fourth; those from the north side of the Kouenlun, and of

the chain north of the Yaru, flow into the great valley of Lake Lhop,

which may once have been continuous with the Amoor river.* [The

Chinese assert that Lake Lhop once drained into the Hoang-ho; the

statement is curious, and capable of confirmation when central Asia

shall have been explored.]

For this view of the physical geography of the western Himalaya and

central Asia, I am indebted to Dr. Thomson. It is more consonant with

nature, and with what we know of the geography of the country and of

the nature of mountain chains, than that of the illustrious Humboldt,

who divides central Asia by four parallel chains, united by two

meridional ones; one at each extremity of the mountain district.

It follows in continuation and conclusion of our view that the

mountain mass of Pamir or Bolor, between the sources of the Oxus and

those of the Yarkand river, may be regarded as a centre from which

spring the three greatest mountain systems of Asia. These are:--1. A

great chain, which runs in a north-easterly direction as far as

Behring's Straits, separating all the rivers of Siberia from those

which flow into the Pacific Ocean. 2. The Hindoo Koosh, continued

through Persia, and Armenia into Taurus. And, 3. The Muztagh or

Karakorum, which probably extends due east into China, south of the

Hoang-ho, but which is broken up north of Mansarowar into the chains

which have been already enumerated.

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'

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.

Himalayan Journals — Volume 2 Or, Notes of a Naturalist in Bengal, the Sikkim and Nepal Himalayas, the Khasia Mountains, etc. · 第 19 / 21 章

The position and elevation of the perpetual snow* [It appears to me,