REPORT OF EXECUTIVE COMMITTEE. 
41 
five degrees less than 70, or 65°, cuts off only a narrow strip 
of Northern Wisconsin, intersecting the north-eastern bounda¬ 
ry at about latitude 45° 30', and passing through Superior City 
in the extreme north-west. According to Blodgett, this last 
average (65°) is sufficiently high to generally ensure the ripen¬ 
ing of Indian corn; and it would therefore appear that almost 
the entire State lies within the climatic range of this, the most 
sensitive and most exposed of our cereal grains; while a large 
portion of the State has an average excess of several degrees 
of heat, over and above what is necessary to perfectly ma¬ 
ture it. 
The isothermals of autumn also indicate a favorable climate 
as compared with the latitude, the mean line of 45° bearing- 
northward in its westward course from a point above the city 
of Green Bay to about the center of Polk county. 
The mean line of 50°, however, takes a different direction, 
entering the eastern boundary at about Milwaukee, and thence 
passing in a south-westerly course to Beloit, near which place 
it crosses the boundary line of Illinois. This shows a tendency 
to a change which, if sufficiently marked, would give the east¬ 
ern portion of the State a milder winter than the western. The 
mean of November (see line touching places with an average 
of 82 c ) shows this tendency yet more strikingly. 
The mean line of 25° for winter barely touches the State, 
cutting off the south-west corner of Kenosha county, and 
thence pursues a course nearly coincident with that of 50°, 
autumn. The mean line of 20°, winter, in its eastward course 
from Iowa, crosses the Mississippi near the northern boundary 
of Crawford county, and thence bears gently northward until 
it reaches Portage City, from which point it takes a more de¬ 
cided northern direction, crossing Lake Winnebago near the 
middle, and striking Lake Michigan near the village of Stur¬ 
geon Bay. The mean of 15° has the same general direction, 
and crosses simply the three north-western counties. Here, then, 
we have this remarkable phenomenon—the isothermal lines of 
late autumn and winter on the one hand, and the lines of spring 
and summer on the other, crossing each other at right angles. 
