finally effected our passage through the Richthofen range (Fig. 4) over a succession of high transverse spurs to the city of Kan-chou. The total mountain area covered by our plane-table survey between An-hsi and Kan-chou amounted to close on 24,00o square miles.
Seven years later, in the summer of 1914, my third expedition brought me once again to this large city of Kan-chou and the great oasis at the foot of the Nan-shan of which it is the centre, just as in the days when Marco Polo stayed there. It was to serve as our base for the new surveys which I had planned in the Central Nan-shan. Their object was to extend the mapping which we had effected in the high mountain near the sources of the Su-lo-ho and Su-chou rivers by surveys of the high ranges farther east containing the headwaters of the river of Kan-chou.
In conjunction with our labours in the Etsin-gol region to be described in the next chapter these surveys were intended to complete the mapping of a well-defined portion of north-western Kansu. This, inasmuch as it sends all its waters into an undrained basin, may well be claimed in respect of its general physical conditions as belonging to Central Asia rather than to China. Previous experience had prepared me for the reluctance of the local Chinese to venture far into those mountains and for consequent difficulties about securing transport. But a fortunate chance brought just then an old Chinese friend to the military command of Kan-chou in the person of worthy General Tsai, whose kindness I well remembered from my visit to Su-chou in 1907. His opportune help enabled us to set out for the mountains by the first week of July.
The route followed during the first marches acquainted
IIIF Color HighRes
