352 Report oF THE HortTicuULTURAL DEPARTMENT OF THE 
it could not be otherwise than that some varieties would be endowed 
with constitutions better fitted for withstanding drought or an 
excess of water, than others. We must count moisture as one of 
the chief factors influencing the distribution of varieties. Not only 
must the rainfall be taken into account but the distribution through- 
out the year must be considered. The amount of water capable 
of being retained by a soil is of considerable importance. Strong 
dry or moist winds greatly influence the supply of water needed by 
plants; this is as true in winter as in summer, for moisture may be 
evaporated from the tree tops in winter by a dry or strong wind, 
or while the ground is frozen so that the normal supply is cut off 
from the roots, and winter-killing thus results. The Russian apples 
are well adapted to withstand the last named condition. 
Soil.— The richness of the soil; its physical characters; its power 
to retain water; and its heating properties are all determinants of 
special adaptations of fruits to a region. but it is not sufficient 
to know that pears thrive on clay, peaches on sand, and apples on 
loamy soils. The varieties of these and of all other fruits have dis- 
tinct preferences. Some varieties, as the Baldwin apple, Bartlett 
pear and Concord grape are cosmopolitan as to soils; but none of 
these, and no variety, is wholly indifferent to even slight variations. 
One of the most important matters before fruit-growers in the 
adaptabilities of fruits and their varieties to soil. 
To some extent we can grow varieties upon soils which are un- 
congenial to them by grafting upon stocks better adapted to the soil 
in question. 
Air currents—Air currents are of minor importance compared 
with the other physical factors but are worthy of attention. Winds 
are beneficial when they bring warm air, when moisture laden, to 
keep frosty air in motion, and sometimes for the suppression of 
insects and fungi. They are detrimental when too dry, too strong, or 
too cold. Natural or artificial windbreaks may greatly modify the 
effects of air currents, though the value of the latter is usually 
over-estimated as their benefits are often offset by their bad effects. 
