inches, whilst the averages for maximum temperatures, minimum temperatures 

 and barometrical records were 82*0° F., 61*2° F., and 24"8i inches respectively. 



During the three and a half months spent at Lan-chou the barometer 

 varied from 24'6o inches to 2530, an extreme variation of 07 inch. The 

 barometer at T'ai-yiian during the three months ending July 31st shewed an 

 outside variation of only 0*42 inches. 



On July 15th the expedition left Lan-chou Fu on its way back to T'ai- 

 yiian Fu, by the same road which it had travelled in the spring. The journey 

 occupied nearly two months, during the whole of which time careful 

 observations were kept. No long stoppages were made. 



On the 17th the party was held up for two days at Ch'6ng-kou-yi by very 

 heavy rains, which rendered the roads through the soft loess country 

 impassable. The rainfall recorded on this occasion was 1*32 inches in ten 

 hours. Unfortunately the rain gauge overflowed during the night so that it 

 was impossible to estimate the exact amount that fell. The head native of the 

 expedition said that it was the heaviest rain he could remember since the time 

 (about 1888) when the F6n Ho overflowed. It then flooded the T'ai-yiian 

 plain, and, entering that city, demolished the Tartar quarter in the south- 

 western corner. 



At Ch'ang-t'ai-p'u the expedition was again held up by rains from the 

 evening of the 25th to the 28th. During this time a total of 1*45 inches 

 fell. Altogether the total rainfall for the month was 4*33 inches. The 

 weather was usually bright and calm, though frequently very hot. 



August found the expedition once more at Ku-yuan Chou, and for some 

 days the weather was fine and calm. Rain fell on the 4th, after which the 

 party experienced intermittent rain, overcast skies, heavy dews and mists till 

 the 25th. The total rainfall for the month was 1*63 inches. From the 

 25th to the 31st the weather was again clear and calm. During the whole 

 month there was scarcely any wind. 



On the 5th the thermometer registered a maximum temperature of 102.2° 

 F. at Ching-yuan Hsien, and '99*0° F. was recorded at Ch'ing-yang Fu. 

 four days later. 



From this date the temperature seemed to fall steadily though some very 

 hot days were experienced in the loess ravines of the country between Yen-an 

 Fu and Sui-td Chou, which place was reached on the 29th. 



The first three days of September were wet, the rainfall being '52 

 inches. From then onwards the weather was clear, with but little wind. The 



151 



