radiation. In the case of the maximum thermometer, it was impossible to 

 expose the instrument during the day when the expedition was on the march. 

 Frequent readings of the thermometer were, however, made during brief halts 

 at the hottest time of the day, and the highest of these readings was taken to 

 be the maximum temperature for the day. In the diary, the readings of the 

 maximum and minimum thermometers are printed opposite the first observa- 

 tion for each day for the sake of uniformity. It is to be noted, however, that 

 the maximum reading refers to the same day as that against which it is 

 printed, whilst the minimum refers to the lowest temperature of the preceding 

 night. 



The highest temperature recorded on the expedition was on July 5th, 

 1909, at Ch^n-yuan Hsien, in Eastern Kansu, when the thermometer 

 registered 102*2° F. in the shade. On July 5th, 1908, at Chao-chuang, near 

 T'ai-yiian Fu, the thermometer registered loo'o^ F. in the shade. On August 

 5th, 1908, the same temperature was recorded within the walls of T'ai-yuan Fu, 

 while on the 8th of the same month a temperature of ioo'2° F. in the shade 

 was recorded. 



The lowest temperature on record was at Kan-ku-yii, near Yen-an Fu, in 

 Shensi, when the thermometer went down to— 6'o° F. on December 19th, 

 1908. At Yen-an Fu, on January 19th, 20th, and 21st respectively— 3*5*^ F. 

 and— 2'5*^ F. and zero were recorded. These records were made within the 

 shelter of the town walls, and it is probable that far lower temperatures pre- 

 vailed in the open valleys outside. 



The greatest rainfall occurred on July i8th, 1908, at T'ai-yiian Fu, when 

 3'66 inches fell in twenty-four hours. On July 17th and i8th, 1909, at 

 Ch'6ng-k'ou-yi, in Kansu, i"32 inches, the next heaviest rainfall, was recorded. 



Cloud formations, and the strength and direction of the wind were also 

 noted daily. 



Good sets of observations were secured at the following places : — 



1. In and near T'ai-yiian Fu, Latitude 37°5i'36'' N., Longitude 



Ii2°33'56'' E., altitude 2600 ft., from May i6th to September 

 28th, 1908. 



2. Yun-t'ing Shan, Latitude 37°54'0ii N., Longitude iii°33'48'' E., 



altitude 6950 ft. in the mountains 90 miles west of T'ai-yuan 

 Fu, in Shensi, from October 4th to i6th, 1908. 



3. Yii-lin Fu, Shensi, on the borders of the Ordos Desert, Latitude 



38°i6'54" N., Longitude i09°45'o'' E., altitude 3170 ft., from 

 November 5th to December 5th, 1908. 



136 



