January, 1909. Yen-an Fu. Alt. 2769 ft. 
January again was a month of extremely cold, but on the whole fine 
weather. The proportion of cloudless days was not quite so great as in the 
last twelve days of December, while light falls of snow, usually following 
stratus clouds, were recorded on the roth, r1th, 12th, 13th, 16th, and 30th, 
Hoar- frosts were recorded daily from the 23rd to the 27th inclusive. In cloud 
formations there was a decided predominance of cumulus, or cirro-cumulus 
clouds, over anything else. Cirrus also occurred with comparative frequency, 
whilst stratus were also recorded more frequently than usual, being generally 
followed, as already stated, by snow. Again the light variable wind was the 
rule, though from time to time it freshened, when its general direction was at 
once discernible. It was then recorded from the north-west, west, and south. 
Wind was not once recorded from an easterly direction. 
From the rgth to the 22nd some very low temperatures were experienced. 
The minimum temperature for the month was —3'5° F. on the 19th, while the 
average minimum was 12°2° F. 
The maximum reading for the month was 39.0° F., which temperature 
occurred on the 4th, 5th, and 28th. The average maximum was 32°1° F. 
The highest, lowest, and average barometrical readings were 27°16 inches. 
26°64 inches, and 26°86 inches respectively. 
Yen-an Fu to Lan-chou Fu. 
On January 30th the expedition left Yen-an Fu for Lan-chou Fu, in 
Kansu. The journey, including many stoppages, was accomplished in a little 
over two months. 
Observations were regularly taken at altitudes, ranging from 2769 ft., the 
altitude of Yen-an Fu to 7468 ft. in the high loess country of Kansu. 
Temperatures remained comparatively low till the commencement of 
March, when the weather began to get distinctly warmer. On April 3rd, just 
before Lan-chou Fu was reached, the maximum thermometer registered 
680° F., and the minimum 32.0° F., and on the morning of April 5th, the 
day on which the expedition entered Lan-chou Fu, the minimum temperature 
was 41'0° F, This was the highest minimum temperature recorded since 
November 4th, 1908. Twice in the early half of February the minimum 
thermometer registered 2°0° F., but no temperature lower than that was 
experienced. 
Owing to the various altitudes of which observations were taken, nothing 
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