CHAPTER V. 
CHANGE OF CLIMATE IN THE PRAIRIE REGIONS. 
Since the advent of civilized man, and the general 
cultivation of the soil, considerable climatic changes 
have taken place in those parts of the Prairie countries 
which have been long settled. The most apparent of 
these changes are: First, greater aridity of the 
atmosphere. Second, more rapid evaporation. Third, 
greater irregularity of rain-fall. Fourth, diminished 
force of the prevailing winds. This statement is 
based on the observation and experience of a residence 
of forty years in Central and Northern Illinois. 
Although these changes are, with the exception of 
the last-mentioned, analogous to the effects produced 
in wooded countries by the removal of the forests, 
they cannot, in this instance, be ascribed to the same 
cause. As has before been said, the amount of timber 
was greater twenty years ago than at the first settle- 
ment of the country; and though the destruction 
has lately been rapid, the entire amount of woodland 
was originally so much less than that of prairie, that 
