highest parts of the country, we had had snow, which was in accordance with our experiences from the winter of 1906-1907. On both sides of it, there was very little snow or none at all. At 3 o'clock p. m. it began to snow again.
On February 1st, we marched 16.7 km. S. S. E. and S. S. W. to Camp CCCXIX, where the height was 5,002 m. or 247 m. below Camj5 CCCX VIII, being a fall of 1 : 68. The temperature of the night was only down at —18.2°, but it snowed continually and the sky was over-clouded. In the morning the clouds were so thick that it was quite dark, and it snowed continually nearly the whole day. The wind was very strong, but now came from the S. S. E. The snow was deep again, sometimes two feet, and the surroundings of the lake, which the day before had appeared dark and bare, were now quite white. Enormous quantities of atmospheric moisture are driven by the S. W. winds, in the form of heavy, compact clouds from the Indian seas across high Tibet. The precipitation no doubt decreases from west to east and from south to north. The highest parts of the country catch the greatest amount of precipitation, as we have found.
It would be easy to draw a map of the snowfall in Tibet, founded upon the experiences I have had. Very little material for such a map would be obtained from the observations of other travellers, as hardly anybody has chosen such a disadvantageous season for his journey as I. It is, however, of great interest to study the winter climate also, of such an inaccessible country as this. In spite of the abundant snowfall we had witnessed ever since the region west of Arport-tso, the amount of snow is never sufficient for accumulating and forming névés and glaciers, as would be the case under other conditions. This is due to the dryness of the atmosphere and the very strong evaporation. Only on the highest mountains, the snow is eternal. The rest evaporates and disappears early in the spring, without even forming floods in the beds and erosion furrows of the valleys. It is very likely that the greater part of the snow-sheet covering the country between ArJort-tso and Shernen-tso, never gets an opportunity to melt and to flow down to the lakes in the form of water. Before the temperature of the spring has become high enough to melt the snow, the snow-sheet will already have disappeared by evaporation. An exception from this rule will probably only be found in the very highest regions, though even there, as for instance on the Chomo-uchong; the melting will proceed so slowly and gradually, that it will never give rise to any large volume of water in the brooks.
Our valley becomes broader and soon opens out to the extensive plain of the lake, where we follow broad and shallow beds going down to the N. W. shore of the Shemen-tso. The usual hard and dry vegetation of the highland steppes, is growing here in belts and ribbons between these broad watercourses. We steered towards the first promontory on the northern shore, but as the country thereabout
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