308 THE LOP-NOR PROBLEM.
The Lop-nor is indeed the last remnant of a former lake-basin of the Hanhai; but in identifying this lake-basin with the great lake of Lop-nor, of which »Karakoschun is the present remainder,» Prince Krapotkin puts back the problem to such a remote period of the world's history that neither Lop-nor, nor Lôu-lan (which he places on the shore of this gigantic lake), nor even the Chinese themselves as yet existed. What we call the Lop-nor problem, the problem we are consequently discussing, has nothing whatever to do with wide-reaching basins of an older geological period, but it is concerned with a period so recent as to come within the compass of actual documented human history, and with the help of human documents we are in a position to follow in part the actual course of the hydrographical occurrences.
Why the lake, after shrinking to the requisite extent, should settle into the eastern part of this triangular area, I do not understand, for no traveller has ever been in that part. In taking the Kara-koschun to be all that now remains of the Lop-nor, Prince Krapotkin is virtually adopting Prschevalskij's standpoint. But when he goes on to say, that the lake »was changing its position in proportion as it decreased, and it may change it several times more», he adopts my point of view, nor can I venture to reconcile these two different opinions. For when the Lop-nor dried up and the Kara-koschun was formed — it was precisely then that the terminal lake of the Tarim system altered its position. Prince Krapotkin calls this terminal basin »the Tarim Lake», a most happy designation, for generally speaking by this must be understood the lake into which the Tarim empties itself no matter whether it be situated in the north or in the south of the desert. When the Tarim lake lay in the north the Chinese called it Lop-nor, but after it migrated to the south it was called by Mongols and Turks the Kara-koschun. Both hydrographically and genetically therefore the Kara-koschun plays precisely the same role that the Lop-nor formerly did, although geographically and topographically they are two different lakes. In other words, it is the same lake occupying two quite different positions; and Prince Krapotkin is perfectly justified in supposing that this migration may still be repeated several times again. On the other hand the Kara-koschun will not become joined with the Kara-buran, for the latter is on the point of being filled with sedimentary matter, and hence of totally disappearing, whereas the Kara-koschun, as we have seen, began to return in earnest towards the north in 1901.
In the preceding pages I have recalled the principal moments in the polemic with regard to the Lop-nor, and have pointed out that none of the English or French travellers who have visited the region has in any degree made the slightest contribution towards the solution of the problem. Nevertheless there is one notable exception, a man who is intimately acquainted with both the geography and the history of Central Asia, who, although he has not himself visited the country of Lop, has nevertheless formed his own opinions regarding it, and that in such a clear and ready way, that I feel I ought not to pass him over unmentioned in this connection. I mean Mr. F. Grenard, who took part in J.-L. Dutreuil de Rhins's journey across Asia in 1890-95, and who has published a very excellent and valuable account of the results of the expedition, under the title of Mission Scienlifique dans la Haute Asie. In a chapter devoted to a general account of the geography, Grenard has occasion to refer to the hydrographical relations of East Turkestan. After discussing
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