236 Report of tHE HorTicuLTURAL DEPARTMENT OF THE 
EFFECT OF THE COVER ON VELOCITY OF WIND. 
Measurements were not made of the velocities of the wind 
under the cover and outside. There was a very great difference 
however. With a stiff breeze blowing outside there was not 
wind enough under the cover to move a sheet of paper lying on 
the ground. With only a fair breeze outside the air underneath 
was calm. 
EFFECT OF THE COVER ON INTENSITY OF LIGHT. 
Measurements also were not made of the intensities of the light 
in the two plats. There was a considerable difference in this 
respect nevertheless. Shadows were considerably less strong 
underneath than outside. Much of the light was in the form of 
diffused light. 
EFFECT OF THE COVER ON EVAPORATION. 
The comparative evaporation from the two plats was deter- 
mined by direct measurement. A large, shallow dish was set 
level on the ground in each plat, filled with water to the brim 
and the depth measured with a metal rule. Measurements were 
made of the amount of evaporation every morning from May 12 
to 25 and June 1 to 5, both inclusive. After each measurement 
the dishes were filled to the brim. 
The record of these measurements appears in Table I. An 
examination of these records shows that the evaporation from an 
exposed surface of water in the open varied from 35 inch to 43 
inch in 24 hours and under the cover from =, inch to ;4 inch. 
The total evaporation in the open for the nineteen days of obser- 
vation was 51% inches, or an average of 0.27 inch per day. The 
total evaporation from the shaded plat was 214 inches, or 0.13 
inch per day. The cover diminished evaporation just about one- 
half. 
Without the aid of instruments of measurement the greatly 
reduced rate of evaporation under the cover was obvious, for 
moisture on the leaves under the cover did not evaporate nearly 
so rapidly as it did from leaves in the open. So much does the 
cover interfere with the drying off of the foliage that Mr. Gil- 
lett advises that it be removed after a rain until the leaves have 
become dry. 
