March 31, 1921] 



NATURE 



m 



Letters to the Editor. 



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The Common Occurrence of Aurora in the South of 

 England. 



Several observers have from time to time reported 

 that the green auroral Hne (A 5578) is commonly 

 observable in the sky at night. 1 have often tried to 

 see it myself with various instrumental arrangements, 

 but without success. Slipher, however (Astrophys. 

 Joiirn., 1919), succeeded in photographing the line on 

 every clear night that he tried. He worked at the 

 Lowell Observatorv, California, as far south as lat. 

 35° N. 



Stimulated by his results, I have succeeded in 

 photographing the line on many nights for the past 

 month. I do not always get it, and one of the 

 failures has been on a fairly clear night. On the 

 other hand, many of the successes have been on 

 cloudy, though not, of course, extremely dark, nights. 



At the present time sun-spot minimum is much 

 nearer than during Slipher 's experiments, and for 

 this and other reasons I am inclined to think that I 

 have been dealing with fainter auroras than he did. 

 Success has been due in the main to the use of 

 Marion's new " iso record" plates, which are very 

 sensitive in just the spectral region which is needed. 



The programme in view is a systematic comparison 

 of the auroral intensity with sun-spots and magnetic 

 disturbances, and also a comparison of its intensities 

 in different localities in Great Britain and elsewhere. 

 So far as I have been able to learn, the auroral spec- 

 trum has not previously been photographed in this 

 country. Ravi.eigh. 



Terling Place, Witham, Essex, March 21 



Mount Everest. 



.\\ important event which will add greatly to our 

 knowledge of physical geography, as well as of all 

 branches of science, has come to pass. The permis- 

 sion of the Dalai Lama has been obtained to our 

 entry into Tibet. For this we have to thank Sir 

 Francis Younghusband for his early love of travel, 

 which took him through so many miles of elevated 

 wastes in Central Asia, culminating in his present 

 influence, the result of a successful military expedi- 

 tion, and the presence to-day of a Political Officer 

 in Lhasa, Mr. Bell. 



The president of the Royal Geographical Society 

 (Geographical Journal, February, p. 73), after sum- 

 ming up what has to be done in the country, says, 

 'Our geography of it must be complete"; lie could 

 not say more than he did in these few words. 



The changed conditions at once opened up the 

 possibility of knowing more of the highest peak in 

 the world, Mount Everest, the surrounding topo- 

 graphv, the best way to it, and, lastly, what will be 

 possible on its flanks. .After all, the supreme advance 

 and gain are centred upon the survey of Tibet ; if 

 this can be extended at any point on the thousand 

 miles or so between Kashmir territory and .Assam, 

 through Rudok, Gartok, Hundes, the northern boun- 

 dary of Nepal, Sikkim, Bhutan, Aka, etc., our suc- 

 cessors mav in time look forward to the possession 

 of maps of the whole Himalayan chain, including 

 its northern side. .Another great advance will be to 



NC. 2683, VOL. 107] 



master the secrets of its internal structure and to 

 extend what we at present know of Himalayan 

 geology to where so few with the necessary know- 

 ledge have as yet penetrated. 



In thinking of a vast countrv one is led to dream, 

 and in the making of this great map my thoughts 

 tell me that the libetans can be employed. Ifteir 

 artistic abilities are great ; art they have practised for 

 centuries. Almost alone among the .Asiatics 1 have 

 known they can use a map intelligently ; they would 

 soon excel in surveying. When I taught a few Lama 

 draughtsmen perspective they were delighted. Thus 

 I am led to contemplate a branch office of the Indian 

 Survey Department at Lhasa, for instruction there 

 would be better for many reasons than in India. 



The Duke of the Abruzzi's expedition to the 

 Mustakh glaciers has been taken as a model for 

 the present one, yet it must not be forgotten that all 

 the conditions are different. In the former case the 

 country was known ; it was in a native State under 

 the control of the Indian Government, and not far 

 distant from a well-populated district with a sufficient 

 supply of food. It did not matter how many Euro- 

 peans were attached to it ; it was carried out 

 luxuriously and at great expense — so expensive was 

 it that I fear these great expeditions will render future 

 travel over the same ground almost impossible for 

 the ordinary explorer. 



For this first advance into Tibet I would have pre- 

 ferred myself, and taken for a model, the work of 

 Sir .Aurei Stein. His topography (the work of two 

 native surveyors) of the Kuenlun range, etc., is ex- 

 cellent, and surveyors with similar training would 

 be the fitte ,t ipen in Tibet. It is unfortunate that the 

 native surveyors, excellent, reallv splendid, men as 

 some of them are, have not the education and know- 

 ledge to observe and write on the country they map ; 

 but we cannot have perfection. 



In a recent article on Mount Everest in the 

 Surrey Advertiser I said: '"Of this I am convinced, 

 the smaller the party and the less fuss made about 

 it the better." This is truer now than when it was 

 first written. From what I read in the papers and 

 from a circular from the president of the Alpine Club 

 the size of the party is indicated and its growth 

 is fast^ — five and a doctor. To this has to be added 

 the survey party. 



.A great deal has since been published from various 

 sources regarding what has to be done before Mount 

 Everest is reached; it is mostly imaginative, for w'e 

 know really nothing, having so little to guide us. No 

 m.ore is known than I knew when I left the top of 

 the Senchal Trigonometrical Station, Darjeeling, in 

 December, 1863. I had been examining the position 

 of Mount Everest far away on the west, and this with 

 a surveyor's eye, noting the points and peaks to be 

 visited and the general lie of the ground. I have a 

 vivid recollection of it ; all remains the same and 

 is common knowledge. The best authorities at 

 present are Ryder, Younghusband, and Bruce, for 

 they have seen the Everest mass at shorter distances. 

 Darjeeling is now the terminus of a railway a few 

 hours' run from Calcutta. This fact much affects an 

 expedition starting from it, which is well set forth bv 

 Lt.-Col. C. Howard Bury in the Geographical Journal 

 for February, p. 121. Still, some things have not 

 altered, and I can confine myself to what I would have 

 done so many years ago had I been deputed to survev 

 the head-waters of the .Arun River — of course, with 

 the Tibetans prepared to see me and with political 

 troubles absent, as they are at present. I would 

 have worked precisely as I had done in the previous 

 summer when I surveyed the Pangkong Lake and 

 the high country of Changchingmo (vide Proc. Roval 



