108 The Principles of Fruit-growing. 
thereon of plants or trees with a large amount of 
foliage will, by the evaporation from the soil and 
verdure, tend to raise the dew-point of the surface 
air as it flows downward into the valley.” 
“A modified form of water protection which is 
valuable in orchards is to spray the trees with 
water. This plan is probably even more valuable 
in protecting from freezing citrous fruits and other 
plants which are not injured until the temperature 
has fallen several degrees below the freezing point; 
for, in these cases, the water will tend to freeze 
before the fruit is imjured, and in freezing will 
make sensible a large amount of heat, thus  pre- 
venting further cooling of the air. For this method 
to be successful the spraying must be continued 
until the temperature rises.” 
Kedzie writes as follows upon the subject :* 
“The vapor of water in the air (and clouds 
also) prevents the escape of heat by radiation from 
the soil and consequent cooling of the ground during 
the night. But for the vapor of water in the air, 
we should have a frost every night in the year.” 
“The old plan of a tub of water under the 
fruit tree, and a rope reaching from the tub into 
the branches, may serve a useful purpose. The 
evaporation from the water in the tub and of the 
water carried up by eapillary action in the rope 
may spread the protecting folds of the water blanket 
over the tree. Such appliances, while of some use 
for a small garden, would be futile for a farm. 
*R. C. Kedzie, “Forecast of Frost,” Lansing, Mich., 1892. 
