18 
COLORADO EXPERIMENT STATION. 
§ 25. The wind record is from the anemometer at the Experi- 
ment Station of the Agricultural College. The anemometer at that 
point is exposed on a tower sixty feet from the ground, but with trees, 
not in all directions, at a moderate distance. The supposition that 
this record represents the wind at the lakes is subject to the same 
uncertainties as the similar use of the rain record. The error can- 
not be great. In the present discussion the wind is not used in the 
comparison, but is given to exhibit the conditions. The effect of the 
wind is to increase the amount of evaporation by bringing unsatu- 
rated air in contact with the water, and to give opportunity for the 
diffusion of the water vapor. From the working formula derived 
from the observations in 1889, each mile of wind increased the evap- 
oration by about 2 per cent. Mr. Fitzgerald’s experiments at Boston, 
indicate an increase of 2 per cent for each mile of wind. The 
amounts are to be taken subject to investigations since made. A 
reduction of the observations made at this place during the past ten 
years should give a more satisfactory and useful formula than that 
mentioned in the Annual Report of the Experiment Station for 1891. 
High winds may affect the record by blowing spray into the tank, 
notwithstanding the protecting shelter. The greatest velocity be- 
tween the different observations is given. Heavy rainfalls may in- 
troduce uncertainties also. 
The observations on Claymore lake for three months in the sum- 
mer of 1897 have not been used, because it was found that a leak 
existed in the tank, and the record involving nearly thirty trips to 
the lake is rejected. The record from August 21 to November, after 
the tank was repaired, is given, as also a few weeks in May. 
EXPLANATION OF THE TABLES. 
§26. The column giving the net loss gives the depression of 
the water surface observed in the period given in the second column. 
The rain during the same period as measured at the Agricultural 
College at Fort Collins, is given in the next column. The total loss 
is the sum of the loss observed in the lake, increased by the amount 
of rainfall which has fallen in the meantime, oris the sum of the two 
preceding columns. 
