586 Plain, Prairie, and Forest. [ October, 
is that in the one case one of the maxima falls in September 
and in the other in October, and that the range is a little larger 
in the more westerly region. We find, on examination of the 
tables, that from about forty to forty-five per cent. of the total 
precipitation of the prairie region comes in the autumn and win- 
ter months, and that these conditions do not materially differ 
from those prevailing in some of the most densely-wooded por- 
tions of the country. To illustrate these points we append a 
table showing the amount of precipitation at some of those places 
in the prairie region where observations have been longest kept 
up, with additional figures from some portions of the densely- 
. timbered country. 
PRECIPITATION, IN INCHES. 
Total, 
Spring. Summer. Autumn, Winter. in Inches. 
10.00 10.34 8.46 7.03 35.83 
Caa BE erie es 9.89 11.25 8.68 7.87 37.19 
Manchester, Ill......... 11.49 8.71 8.76 8.83 37.79 
O E eo tee a esas 11.55 12.04 8.55 7,48 39.62 
10.44 2,50 9.45 8.86 41.25 
innebago, Ill......... 72 2.31 9.66 6.14 37.83 
Platteville, Wis......... 9.88 3.63 9.32 6.48 39.31 
s OWE e.. 7.10 0.53 9.38 5.23 32.24 
Muscatine, Iowa....... 11.92 3.79 10.35 6.82 42.88 
Iowa City, Iowa....... | 11.27 3.04 13.11 5.70 43.12 
Citiiton, lowa... ss secs 11.40 3.94 10.40 7.98 43.72 
Davenport, Iowa....... 10.70 13.71 8.56 6.49 39.46 
St he” Seated 12.42 3.04 9.07 7.65 42.18 
to w Michie) ss. 5.4 7.44 6.48 6.44 25.79 
Marquette, Mich........ 6.49 9.02 8.11 6.39 30.01 
Fort Brady, Mich....... 5.06 9.59 10.68 4.99 30.32 
Detroit, Mich...........:| 8.51 9.29 7.41 4.82 30.03 
Ba 
The last four places are situated in thickly wooded regions, 
the others are on or near the prairies, and they include nearly all 
the localities in Ilinois and Iowa where observations have been 
kept up for as much as ten years. Attention is called to the sma” 
annual amount of rain in the densely-timbered districts border- 
ing on Lake Superior and Lake Huron, and also to the fact that 
there the statistics of its distribution through the seasons are 
much more unfavorable to the growth of forests, according t0 
Mr. Foster’s theory, than anywhere on the prairies. ps 
In view of the above figures it may be unhesitatingly affir , 
that there is no basis for the theory that an unequal distributio? 
of rain throughout the year brings about a treeless condition 
the surface. It is surprising that those who maintain that : 
deficiency of winter rain prevents the growth of trees should n° 
; 
i 
] 
