Page:Mongolia, the Tangut country, and the solitudes of northern Tibet vol 2 (1876).djvu/258

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234

ATMOSPHERIC PHENOMENA.

constant night frosts (16° Fahr. in the first week of May), and though by the 13th of May twelve kinds of flowers had blossomed, it was generally in very small numbers, by ones and twos under stones and bushes, where they were protected from storms. The wind and snow continued to the second week in May; indeed no rain fell, whilst snow fell on seventeen days. Moreover, the wind blew hard and incessantly by day and night, most frequently from the east or from the west; but it varied much, constantly shifting from one quarter to another, and sometimes coming in violent gusts. While these gales lasted, and for hours afterwards, the air was laden with dust from the neighbouring deserts.

Notwithstanding the abundance of the atmospheric deposits and the humidity of the soil, the watercourses contained less water than in the summer, and many were quite dry; whilst the psychrometer indicated considerable dryness in the air on those days on which it neither snowed nor rained. The first of these phenomena is probably due to the circumstance that the frozen earth imbibed a great deal of the moisture which fell; and the dryness of the atmosphere in clear weather was doubtless caused by the influence of the surrounding barren plains, which were at this time quite parched.

We had no fine spring weather. Occasionally it would clear up at midday, but the wind would again rise, bringing more snow and a lower temperature. The hottest day was the 24th April, when the mercury stood at 68° Fahr. in the shade; whilst the