138 



SMITHSONIAN MISCELLANEOUS COLLECTIONS 



VOL. 



65 



Figure 10 shows mean hourly temperatures at Mount Whitney and Inde- 

 pendence and for the same period during 1893 and 1894 at Pikes Peak. The 

 range at the latter appears to be somewhat smaller than at .Mount Whitney, 

 and this may be due to the fact that conditions at Pikes Peak are more nearly 

 like those of the free air, owing to its isolation and the consequent freer 

 circulation. The curve for Independence shows the large diurnal range 

 characteristic of valley stations. Beneath the mean temperatures for Mount 

 Whitney in table 6 are given the means for the same period at Independence 

 and the differences in temperature change per 100 meters altitude between 



Fig. 10. — Mean hourly temperatures at Mount Whitney and Independence, 

 Cal., August 3 to 12, inch, 1913, and at Pikes Peak, Col., August 3 to 12, inch, 

 1893 and 1894. 



the two places. The temperature change with altitude during the night hours 

 is somewhat misleading, owing to a marked inversion of temperature between 

 the surface of the valley and about 200 meters above it,- as will be pointed out 

 in discussing the Lone Pine observations. The hourly differences between 

 Independence and Mount Whitney during the daytime are large, averaging 

 about 0.85. The mean for the 24 hours is 0.73. 



The relative humidity, table 7, was probably higher than normal for this 

 season of the year, owing to the unusually stormy weather and the presence of 

 snow on the ground. The mean was 69 per cent, the mean maximum 79 per 

 cent at 7 to 8 p. m., and the mean minimum 61 per cent at 4 a. m. During the 

 severe storm of August 8, 9, and 10, 100 per cent was frequently recorded. 

 The absolute minimum was 15 per cent at midnight of the 12th. 



