*1
Khassya Mts. Sep. 23./ 1850
To Baron Humboldt My dear & honored Friend
My correspondence has inevitably fallen into such confusion for the last 12 months, & so many of my letters have been lost, that I am almost afraid to think how long a time may have elapsed, since you heard from me:---- much longer, I know it is, than it ought to have been, under any circumstances, & especially as I have never thanked you for the distinguished place you are said to have given my name in your new Edition of the Aspects of Nature. My copy of this work has not reached me, but I am very well aware that I ought to be very grateful, & to feel highly honored. I have very much to thank you for, during many years.
I acquainted you with my fruitless application to the Surveyor--General for information about the heights of Dwhalgiri [Dhaulagiri], Gossain--Than [Gosainthan or Shishapangma], &c &c. He never answers letters. Dr. Campbell, who since addressed him on the subject, has met with no better success. I believe that he has not calculated any, but Chumalari, & Kinchin--Junga [Kanchenjunga]. There are 4 Peaks, which the Surveyor--General considers as rivals, & within a very few feet of the same elevation:-- & I hear that he states them thus.
1. Kinchin-- Junga. 28,148, feet. (accurately measured.) 2. A Mountain in about 86°. 30' E. Long. -- -- -- -- -- 3. Gossain--Than -- 4. Dwhalgiri. -- Jewahir is considerably lower than any of these.
The Deputy--Surveyor--Genl. (Capt. Thuilliers is an intimate friend of mine; but he can give no information, his Principal not having forwarded any results, or data, to the Office at Calcutta *2. Probably I have already told you the same as is detailed above), I know no more. The Mountain, No. 2, I have repeatedly seen: it divided the Rivers

Arun & Kosi, & it is visible from Darjeeling & elsewhere. You are aware of my visit to the two Thibetan [Tibetan] Passes, in Eastern Nepaul [Napal], to the West of Kinchin--Junga, in Nov. & Dec. 1848, & of my protracted residence on the Sikkim frontier, in June, & my subsequent visit to 5 other Passes, in Oct & Novr. 1849. During the latter Excursion, Dr. Campbell joined me, & we were eventually imprisoned by the Sikkim Rajah, his Counsellors &c. Our lives were threatened & Dr. C[ampbell]. had a most narrow escape & was treated with great barbarity.
I had previously visited Thibet & spent some days North of lat. 28°., discovering the source of the Arun River, which flows from the West of the Kamtchoo Lakes, behind Kinchin--Junga, to its exit from the Mts. of Thibet in Nepaul. From what I saw, & from the very full information which I collected, I am now convinced that the Snowed Himalaya do not form an individual Mountain--Chain; but that they consist of groupes[sic] of snowy Peaks, widely separated from one another, & are parts, or individual spurs of a far more lofty range of Mountains, between the great masses of snow, & the Yarou--Tsamper river. The Southern water shed is behind all the snows, often 1/2 a degree & more; & the Thibetan frontier was along the line of watershed behind, as often as along the ridges of snow. Thibet, between the Yarou & the snow, is, as you have well described it, a lofty rugged & quite impracticable country; though none of the Peaks, North of the watershed on that line, reach the elevation of the snowy ones.
The Snowy Peaks, called Himalaya, occupy Noeuds of great elevation, & whose surface is less rugged. The Rivers, too, throughout Thibet, run in broad open valleys, with rugged scarped flanks. Except along the courses of the rivers, the country is uninhabited; & almost impracticable: détours of any extent are preferred to crossing the chains in Thibet. Of these great Noueds I recognize 9, well--marked, & separated by an unsnowed tract of comparatively low elevation. These are,--

1. A Groupe[sic], in long[itude]. 93,° (which I am now measuring) dividing the Soubanshiri from the Morass. 2. A groupe[sic] I am also observing between the Morass & Patchion. 3. Chumalari Groupe[sic], between Patchion & Matchoo, which rises North of Chumalari. 4. Donkiah (24,000) which I have visited, between the Matchoo & Lachen or Teesta 5. Kinchin--Junga, between the Teesta & Arun. 6. The Peak (previously mentioned) in 86°. 30,', between the Arun & Kosi. 7. Gossaim--Than, between the Kosi & Gundule. 8. Dwhalgiri, between the Gundule & Gogra 9. Jewahir & Mansarovar. ?
The unsnowed space, between No. 5 & 6, is very great. East of 1. both the Snowy Himalayah arrest & the lower ranges sink greatly. I am now nearly due South of 1 (S.10.° W.) & see the horizon, to 30.° East, without a snowy Peak or Elevation. The Snow commences again, East of the Dihong, which I do not doubt is the Brahmapootra & Yarou. All the Rivers, mentioned above, as between the groupes[sic] of Snows, have their sources in a small, well defined Range, South of the Yarou. That range forms the boundary of Nepaul. West of Gossai--Than, -- it did form the boundary East of it, before the war between Nepaul & Thibet. East of Gossain--Than, there is no natural boundary; except where the spurs of the mountains, East & West of the exit of the Arun, constitute one. The Thibet Boundary of Sikkim is Kinchin--Junga, to the West; & the range between the Lachoong & Teesta in Thibet,-- which is a westerly spur from Donkiah, which last runs South for 40 miles, via snowy Meridional Range, Chumalari does so, too; & the Chinese have drawn the Line, South from the Eastn. flank of the Donkiah, for as many make miles, & then North again, from the West flank of the Chumalari. This V--shaped bit includes great part of the Machoo's course, & the Town of Puri: it is interposed between Sikkim & Bhotan [Bhutan]. The Palchion Valley is as low as 6,000 feet in the

latitude of Chumalari, & looking from Thibet, S. East, I could discern a snow between the Chumalari & the groupe[sic] East of the Patchion. This last Groupe[sic] I also see from these Mountains where I now am. distant 210 miles & I calculate its elevation at near 24,000 feet;-- from both stations. When I was in Thibet, in lat. 28°.10 N.., & Long.88°.E., I took angles with a Theodolite, from a mountain, 18,500 above the sea, on the Southern flank of the Arun valley. The ranges, to the North of me, were no where below that elevation; but they did not rise above 22,000ft. Eastward I saw three Meridional ranges, i.e. that of Chumalari to the S[outh]. East, & 2 others, each of which came from a lofty mountainland, & were connected with a beautiful snowy range, about 80 miles to the N[orth]. East, & which I believe separated the U & Tsang Provinces of Thibet. North West of me was the course of the Arun, & beyond it, a very lofty range, rising to 25,000ft., which took a southerly direction forming the Snowy Himalayah Groupe[sic], between the Arun & Kosi(or to West of Kinchin--Junga.) This line of watershed is a physical feature much recognized by the Thibetans: between the Arun & Chumalari it is called Dingchaun Province, & sometimes Damtsen. The Inhabitants are very black: they rear shawl wool goats & Yaks, & are a most turbulent race of robbers, detested as savage cattle stealers, or worse, by the Sikkimites Nepalese & Thibetans. To us they were uncouth, rude, & boisterous & could only be kept in order by great bullying. They opposed my crossing the Arun & I owe them a heavy grudge for breaking my Azimuth Compass, though I believe the mischief was caused by accident & awkwardness, rather than deliberate ill will.
Kiong--lah is the name of the Range forming the great axis or water shed, between the Yarou & Arun. Turner crossed Dingchaun & reached his highest ground about Ramtchin. That is the centre of the Noued:-- from thence, 6 mountain--chains, or spurs, radiate, they are 1. That, West of Bhotan, on which is Chumalari. 2. That, East of Sikkim, with Donkiah on it.

3. That, bounding the Arun on the South. with Kinchin--Junga (4.) 5. The axis, running N.W., between the Panasa Painom & Arun & then S.W. 6. The Odoo Mts. (?) running S.E. between the Patchion & Morass. = The rivers are (1)S. the Matchoo (2).S.W. the Teesta. (3) W. the Arun. (4).N. the Painom. (5).N.E. --?-- (6.)S.E. the Patchion.
The mean elevation of this tract is 16--17,000 feet: nothing will ripen there. Digarchi is in about Latitude & Longitude that Turner assigns to it: there the crops ripen only under the shelter of, & favored by the radiation from, the black rocks of the flanks of the Painom Valley, & its Tributaries:-- the Wall nut grows, but neither it nor the Peach ripen fruit, & Willow is the only tree.-- it is from 8--12 feet high.
The result of all the oral information gained about the native & the cultivationted vegetation of this region lead me to assume its elevation at 14,000 feet; & the mean Temperature of Octr. (fide Turner) gives the same, calculated at the rate of 1°. degree of Fahr[enheit]. = 400 feet., which, from a multitude of observations on the air & sunk Thermometers (3ft.) contemporaneously with others, at Darjeeling & Calcutta, I have found to be the decrement for altitudes above 1,000 feet, North of the Snows. In "Asie Centrale" you perhaps assume Turner's Oct. Temperature of Digarchi for that of Lhassa. Of Lhassa I have many good accounts. Grapes do not ripen there, but are imported. Peaches. Willow & Wallnut thrive well, whether as regards wood or fruit, but no other Tree. Dromedaries abound. Lhassa is a poor place, after all that has been said of it: the census is small (I forget what.) The accounts of those who have & who have not seen such Town as Purnesh in Bengal are sufficiently different & instructive. The Yarou is navigable for Skin Boats, in the rainy season, from Giatchi to Digarchi, & from it flows, between lofty mountain ranges, far East of the great Lake (I forget its proper name, not Yarbough, as it is called on the maps): it is

certainly very large, but the Island is small, towards the S.W. angle. the Yarou trends South, & the country is warm, producing the Mulberry & some say Silk & Rice. Every Thibetan describes the people near the bend, as atrocious Savages, dwelling in mountainous woods, bordering Assam: they are the Arbors & Bor--Arbors, of course. There the Yarou (they say) enters the Mountains, & flows S. to the Brahma--pootra. The stream is there too rapid to admit of navigation & the inhabitants of its banks are too savage. East of Bhotan, by Towang, there is no snow, en route from Assam to Thibet, & Juniper grows to the mountain--tops. The Rivers, from a little way South of the Yarou, flow to Assam; Nor is the boundary of East Bhotan well--defined. All the various information which I gained respecting the Yarou, was to the same import, & my informants were very numerous. The best was a well--educated monk, who was brought up at Mendoling, a Goompta, 2 days South of the Yarou, situated on a river, flowing to Towang, & Assam, 5 days off. Menchona is the North of that quarter, & the only great one East of Puri. North of the Yarou is the Salt--country, lofty, rugged, barren & inhospitable to the last degree. The Yak cannot proceed beyond a few marches North of Digarchi, & sheep are almost the only Beasts of burthen, except Men.
Respecting the Physical features of Eastern Thibet, its manners, customs & agriculture, religion, &c, I gleaned many particulars; but I fear they would only weary you. Your general account is admirable. Plains, as you say, are but local features, & very limited ones:-- the country is one of stupendous, rugged mountain--chains,-- & not of Plains or Tableland. The flat--floored valleys & scarped--flanked mountains are of comparatively uniform elevation above the sea, but widely variable as to their heights above the valleys, giving to East[er]n. Thibet a very different look from the Snowy Himalaya. The absence of snow & wood completes the illusion; & as you truly remark, the Traveller, who suddenly comes upon the features of an open country, the access to which begins abruptly, is very apt to be deceived (in its elevation): the Theodolite alone can

dispel the error. The Line of Perpetual Snow is about 15,000 feet, where the masses of the Mountains first rise so high; it gradually rises with the increasing height of the land to 19,000ft.,-- & 19,500 is the lowest mean level, in Lat. 28°. 30', Long. 88 East,-- & 15,000 in the same Longitude & Lat. 27°. 30'. I have seen well defined patches lower down on the south flanks of Kinchin. Glaciers abound, but not towards the Southern limits of the Perpetual Snow, where the mountains are too rugged.
It is a remarkable fact that every River Valley which I have ascended opens out & becomes broad & flat--floored, at about 10,000feet: it becomes imperceptibly more & more so as you ascend; & when it has conducted you above the limits of clouds, rain & snow, it gradually becomes drier, barren & more Thibetan.
The average Rain--fall at Darjeeling is 120 inches, & it is progressively less in the Interior till the mountains reach to 15,000 feet, when the quantity of rain suddenly diminishes.
The first Snow descends on the Sikkim Himalayah at 15,000ft., in September, & does not always melt. In Sikkim the Snow Line descends in Oct.,-- in Thibet not till December. In the drier mountain parts, again it melts up to 17,000ft. In Thibet, as far North as Kiong--lah, snow often falls in the end of Augt. & Sept. every year, & melts again to 19,000ft. As the Rains are not over till Oct. the sporadic falls are numerous & quite disguise the Perpetual Snow.
You have correctly appreciated the many complicated phenomena of Precipitation, Evaporation, Solar & Terrestrial Radiation. These all act differently, whether as to amount, duration, affect, at different seasons of the year, North & South of the Snowy Mountains. Still their effects are progressively greater, in going from the Snows of the Himalayah to those of Thibet.
If I were to compare Sikkim with the N.W. Himalayah, I should say that the snow line is lower in Sikkim, because a far greater quantity falls, & the sky is more cloudy.

With regard to the Mountain Axis in Asia, I do not doubt it is the Himalayah, i.e. the mountain--mass, between the Yarou & the Plains of Bengal.
The greatest mean Elevation is probably 18,000 feet: it is North of the Snowy Himalayah & zigzag:-- proportionally very little of the Snowy Himalayah rises above 18,000ft.;-- & the 300 feet of that, which is exposed to view in a straight line, gives the delusive effect of a mountain--chain, on this side the main axis & water--shed.
I have the pleasant company of my old friend & College companion Dr. Thomson, (of the Scientific Mission to Thibet): he is a man of great enthusiasm & the highest scientific attainments. Before we met, he had, independently, adopted the same view of the Snowy Himalayah as I did in Sikkim; & all that we can see from these mountains appears to confirm it. Dr. T[homson]. has visited the Karakoran Pass, & finds it as laid down in your map to Asie Centrale. He regards the Karakoran & Miztagh as the real continuation of the axis, which runs N.W. from Mansarovar. The latter is, indeed, another noued, from the Sutlej, another North of the Indus, & another South of the Sutlej. In fact, the course of the Indus & Sutlej much resembles that of the Soubansiri & Yarou, the latter being the Dihong & finally the Brahmapootra.
With regard to Atmospheric Phenomena, I found the S. East wind to prevail up to 18,000 feet; whereas, at 24,000, the westerly current is perennial. The S.E. wind is all but perennial, in Sikkim, but is considerably checked by the Himalayah; still, it keeps Thibet cloudy & showery from May till Octr. The S. East Monsoon hardly reaches Sikkim: the current, being generally between the Garrows & the Rajmahal Mountains, cause the Sikkim Himalayah to be much wetter than the Bhotan Mountains, which are sheltered by the Khossyeh. In these

latter mountains, the rain is excessive: 350 inches fell last year at Churra & 120 this last July-- I have, several times, carefully measured 11 inches in 12 hours. There is no error in my Instruments, nor in those established at CalcuttaChurra The Atmospheric pressure Temperature & the Wet Bulb I register as often as possible, without interfering with my other pursuits; & I find that a Thermometer, buried at 3 feet, gives very valuable results.
The Atmospheric Tide is uniform, as to time, at all elevations; but the amount gradually diminishes, & progressively with the elevation; -- at 17,000 feet it appears to be but a few thousandths of an inch. I almost invariably read off all the Instruments 7 times in the 24 hours; & I have horary observations, from all heights, up to 16,000ft.-- I take the same times as at the Calcutta Observatory.
For Geodetical Observations I have little leisure, & confine myself to a careful survey of my route; & occasionally I note the elevations of remarkable distant mountains. The Survey & numberless Barometric Observations, over all parts of Sikkim, may afford elements for a computation of the mean mass of that section of the Himalaya. I have found vegetation up to 18,500 feet in Thibet herbaceous plants are sufficiently abundant at 18,000 in certain spots; & among Shrubs I have several species of Lonicera, & Rhododendron, from above 17,000 feet, with Graphalinea, & Ephedra. A Nettle (Urtica) attains this elevation; so do Zannichellia & Ranunuculus (in water.) Compositae are decidedly however, the most alpine order; many genera, Graphalinea, Saussurea, Artemisia & Erigeron, occurring between 17,000 & 17,500 feet, along with Astragalus & Valeriana (Nardostachys.) A Coleopterous Insect, allied to Meloe(?), & Acarus are found, inhabiting 18,500 feet, along with the Kiang or Wild Ass, & various Ruminants: there too, the Fox, Hare, & two species of lesser Rodents burrow, all of which have Parasites. At 17,000, Bees live & feed: Diptera are common:

Ephemera is found & Papilionaceae of two Genera (Polyommatus & Argynnris) The large Carabidea, which are seen on the European Alps, do not inhabit the Himalaya, & their absence is an anomaly. At 16,000 feet I have observed the Horsefly & the Lumbricus. The Musk Deer I never detected, even in Midsummer, at very high altitudes, never above 12,000 feet; there is, however another species in Thibet. A monkey inhabits the woods at 11,000 feet, but is more common at 9,000. The limits of the Pines are very curious & well marked, differing from Bhotan & the N.W. Himalaya. There is no Deodar. nor Pinus excelsa, nor Gerardiana, nor Cupresses torulosa, whereas the C. Funebris(?) of China is commonly planted: & there is a Wild Larch (Pinus longifolia) at 1,--4,000 ft. -- Yew (Taxus) 17 7,--10,000ft. -- Abies Brunonis, Larch & Abies Khutrow (alias Smithiana) all grow between 8, & 11,000 feet. An erect Tree--Juniper & fruticose Rhododendron (8ft. high), Birch. Willow & Pyrus, ascend to near 15,000ft. in favourable situations, & are all stunted. Lonicera are, however, the common shrubs at 14,000 feet (several species of the genus), with Rosa, & Berberis.
My Geological notes want all to be worked up. Gneiss is the prevalent formation, between 7 & 17,000ft.; above that Encrinitious (?) Granites; & in Thibet, fossiliferous Limestone & Tertiary Rocks. Below 7,000 feet, the Mica & Clay & later, Sandstone & Coal. There is no Lime, in Sikkim--proper, -- except as a Deposit. Hot--springs, of temperature 110°., I have found, at 17,000ft., with sulphurous Salts. The most curious & novel Geological feature consists in the magnificent moraines, which abound in every valley, descending from the Snow. They commence at 10,11,000 feet, & thence may be traced continuously up to the Glaciers themselves whose lower edges, often 20 miles higher up the valley are always at about 17,000 feet. The proofs seem therefore evident, of a gradual sinking of the Himalayas. I could perceive no signs of a rising, but abundant evidence of the contrary phenomenon. The Glaciers have certainly receded 7,000ft.

And now it is high time to draw this long letter to a close: I fear I have but poorly succeeded in my attempt to inform you of what I am about.
Dr. Thomson & I mean to continue our explorations till Novr. in this neighborhood. We shall then visit Cachar, Chittagong & Arracan, from whence we embark for Calcutta & England in the spring of next year. Our conjoined collections will be enormous: his contains 4000 species, from the Plains of India, Thibet, the N.W. Himalaya, Kashmir & Lahore:-- mine nearly as many, from the Sikkim Himalaya & Bengal. We have gathered, together, upwards of 3,000 species more & we expect to add perhaps another thousand from Chittagong & Arracan. The vegetation here is perfectly wonderful: we have 20 Oaks alone, from the Khassyah Mts. & an equal number from the Himalayah.
You will be sorry to hear that Mr. Hodgson of Darjeeling has been, & still is, seriously ill: he always desires his grateful regards to you, when he knows I am writing. I rejoice to hear of your continued health. The news of the King of Prussia's accident reached me here:-- I knew it would afflict you: & I now rejoice, with all the scientific world, that a sovereign who has the true interests of Science so much at heart, has recovered.
Believe me, with feelings of grateful & affectionate regard, your faithful & obedient friend | (signed) Jos. D. Hooker.