My dear Darwin

Here at last I take up my pen to write to you again, & to assure you of my thoughts of you not having slumbered during this long interval in my correspondence I enclose some scraps though hardly worth the Postage to England. I received your kind & full letters 2 months ago & deeply I sympathize with your wifes & your own pleasure in knowing your health to be really improving— It is most kind of you to give me the details you do, which interest me exceedingly, allowing of my drawing my own conclusions as to your bodily health.

Probably I spoke too strongly about your specific work & Barnacles,¹ but really I was in periculosis when I wrote & much harrassed in mind & body.— was in short seeking & finding a very great comfort in wrapping you round with all my thoughts. I remember once dreaming that you were too prone to theoretical considerations about species & unaware of certain difficulties in your own way, which I thought a more intimate acquaintance with species practically might clear up. Hence I rejoiced at your taking up a difficult genus & in a manner the best calculated to throw light on specific characters their value &c. Since then your own theories, have possessed me, without however converting me & interested as I am in the Barnacles & felt desirous of knowing in what direction they had carried your other views

I have been somewhat disappointed in my expectations of finding that Sikkim would tend to clear up your doctrines to my mind. I thought that the transitions from one form to another would be more apparent in a country where under a perfectly equable climate the floras of the tropical temperate & Artic zones blend in the same Longitude & Latitude. Such has not been the case I think. As a flora it is one of better marked species than most countries possess. Its many willows are all well marked species, which is not the case with their congeners of excessive climates (N. Am. for instance) & the same is far more palpable with its Rubi, Senecios, Gnaphalia &c &c. All these being very large genera in both the Himalaya & Europe & N. America (except Rubus.)²

You reason rightly about my Pons petrosa of Yangma valley—& shew how far superior a philosophical mind is to a careful eye— It is undoubtedly a vast moraine, 4 or 5000 ft below the present level of glacier Ice. But I have seen so much since then, that I scarcely know where to commence & how to give you any idea of the nature of the objects (let alone their grandeur) which have at last led me to I hope definite views on the subject of Himalayan Geology, & geography. Rivers & Mt chains met with where least expected & flowing where they should not, have obliged me to reject the Himalaya as an independent chain of Mts—& to seek the axis of the great Mt system between the Yarou river & plains of India, far North of the Snowy chain. Our rivers all rise beyond the Snows & flow through them Southward— The Snow is deposited & retained on the lofty inosculating Southern spurs of the Mt. mass, & being all brought by a S.E. wind Snow does not reach the rearward ranges, of which these form a part. Then too a NW. wind prevails perennially which being dry admits of a cloudless sky, & unequalled evaporation supervenes, hence the main cause of the Snow line ascending to 20,000 ft. beyond the Snowy range whilst it rests at 16000 & below that, where it first meets the chain. That the glaciers of the Himal: are unrivalled in the Tropical or temperate world I am now convinced, as also that they are receding remarkably— I have traced old moraines continuously up many valleys for 20 miles from 9000 to the average level of the recent glacial level at 16 or 17000 & 18000 in these valleys down which those streams flow which arise from beyond the Snow.—³

The great Himal. rivers all rise beyond the snowy so called Himal: from the far less snowed axis behind. The mean elevation of the said posterior axis is far greater than that of the country along the line of Snow, but individual peaks of the latter rise much higher than any of the great mass behind. Hence it is in some part a double chain like yours Andes, or as Falconer expresses it the Snowy chain is an outcrop along the Southern face of a stupendous broad mountain mass, occupying central area of unknown dimensions.— Thomson⁴ & Falconer both regard the greatest Asiatic axis, as a sub meridional one, & running from Mansarovar to Lake Lop—from which chains branch off E & W.—Himal—Karakoram or Mustagh—Koen-Lun—Tian-schan &c &c.

The rarity of glaciers & their small size towards the southern edge of the belt of perp. Snow is I am now sure the simple result of the excessive steepness of all elevations of 15000 ft— Leaving the plains of India & advancing North through Sikkim—we find the greatest steepness at the mountains at 12–17000 ft. Above that & beyond the Snowy range the country is far more open— This is most remarkably seen in following any of the main streams which meander above 10000 ft or 15000 ft though flanked by excessive steep mts.— Ascending they meander still more, & if we follow them, a gradual transition from the rugged Snowy cis nivean regions to the open rocky trans nivean Thibetan region is found.⁵ Generally however the roads cross the Snowy spurs in preference to winding along the rivers & hence the apparent precision with which Thibet is defined. The whole Mt. system is however incredibly complicated & I exceedingly doubt Humboldts system⁶ of 6 Mt chains—4 transverse, the Himal. Koen Lun Thian schan & Altai—& 2 vertical, the Boloor & Chinese range whose name I forget

HC.⁷ Bot Gardens. April 7^th. 1850 Dear Darwin

Here I am staying with Falconer! he played me another sad trick since last mid summer keeping all my letters & overland parcels for 5 months: deaf to all my letters whether written from Camp or prison till I had to come down on him after due warning by the intervention of powerful friends in Calcutta. He sent 7 of Miss Henslows letters, of as many months—& various overland parcels— he had no excuse to offer & plead none— I flared up & forgave all, & visited him immediately on my arrival in Calcutta. Here I find him in capital health & spirits, living by rule enthusiastic in his pursuits as Botanist horticulturalist & Landscape Gardener—⁸ He is fat & looks far better than he did in England—is as great a favorite as ever & most liberal with his garden duplicates. His conduct—dilatoriness in the affairs I allude to incomprehensible as it was arose from nothing but insane procrastination. I never mentioned it to any one at home but you—& now we are together it is never alluded to in any way— His society is as ever delightful & a more amiable fellow never lived. He never goes to the As. Soc. & has dropped all his interference with their ways & doings. for the better or worst.⁹ This morning brought your kind letter of February, whereby I learn that the cold water system has wrought you much good but not a cure—as also that you are the happy father of 7, upon which I wish Mrs Darwin & yourself all congratulations. I came down to Calcutta to persuade Jung Bahadur¹⁰ to give me leave to travel in Nepal but he cannot guarantee me safety during his absence on a mission to England—& I therefore am off at once for Sylhet then Khassya hills & Munnipore.¹¹ Thomson joins me. This is post-day & we are dreadfully busy, so you must excuse my saying more. Best regards to Mrs Darwin & love to the children. | from yr ever affectionate | Jos D Hooker. Address HC. Bot. Gardens. as usual.