72 BULLETIN OF THE 



Evaporation. — The mean of the maximum evaporation of water 

 during the 24 hours for eleven days, was six times greater than 

 when the water was kept in the shade and protected. 



Wind. — The general direction of the wind was from the quarter 

 between N. W. and S. W., or from the mountains to the plains. 

 The proportion from this quarter during the 60 days was 53 per 

 cent.; from S. W. to S E. 25 per cent.; from S. E. to N. E. 12 

 per cent. ; and from N. E. to N. W. 10 per cent. The general 

 direction of the upper strata, as inferred from the movements of 

 the upper clouds, was from N. W. to S. E. The wind was, at 

 times, very strong, and frequently continued so day and night, 

 constituting, as a rule, dry gales. Its velocity ranged from two 

 miles to 43.7 per hour, there being few occasions on which it was 

 entirely calm. The velocity per day varied from 167 to 760 miles, 

 the average being 332 miles. 



Rain. — The total quantity of rain which fell, including melted 

 snow and hail, amounted to 2.55 inches. 



Electrometer. — The observations for atmospheric electricity 

 taken on 25 days show that the kind and intensity followed no 

 general law; that positive electricity prevailed during the fore- 

 noon ; negative in the afternoon, and about equally divided at 

 noon; while the omission of I'esults at certain hours and days 

 during the same period shows that in clear and even partially 

 clear weather, no trace of electricity was discovered, or if it ex- 

 isted, it was too feeble in amount to be detected by the instrument. 

 Three hundred quarter inch sparks per minute were frequently 

 noted during a thunder storm, or during the prevalence of a storm 

 in the mountains to the westward. 



Gaiiella Bypsometers. — The mean of 14 determinations of the 

 boiling point, on eleven days, was 197^.33, the mean corrected 

 barometer for the hours of observation standing at 22.309. 



The weather during the 72 continuous days which the party 

 spent at Sherman was characterized by excessive cloudiness ; by 

 high winds from the N. W. and W. ; by the suddenness with 

 which the sky would be obscured and then become clear again ; 

 by the various directions in which dilterent cloud strata would be 

 moving at the same time; and by a positive uncertainty in regard 

 to the duration of any favorable opportunity for astronomical 

 observations. The altitude was probably a little too gi'eat, as 

 the summit was frequently enveloped in a fog or passing cloud 

 when it was clear weather a few miles lower down the mountain 

 slopes. 



The dryness of the air, so much to be desired in astronomical 

 work, may be illustrated by the following facts : rapid evapora- 

 tion; unusual and almost immediate shrinkage of newly cut lum- 

 ber ; no perspiration ; no animal putrefaction, and no mould. 

 The dew-point was invariably lower than the temperature of the 

 air, and hence there was no dew,> The absolute amount of moist- 



