REPORT OF EXECUTIVE COMMITTEE. 
39 
CLIMATE. 
Distribution of Heat .—The latitude of Wisconsin would in¬ 
dicate a rather cold climate. Meteorological observations have 
demonstrated, however, that the mere circumstance of latitude 
is an unsafe criterion by which to judge of temperatures, since, 
within a given zone, owing to peculiarities of position and con¬ 
figuration of surface, it not unfrequently happens that the 
terms north and south lose all their significance as indices of 
the distribution of heat. In other words, the isothermal lines, 
or lines of equal temperature, pay nothing more than a gen¬ 
eral regard to the lines of latitude, and are often very tortuous 
in their course, crossing and re-crossing those parallels in grad¬ 
ual, or in sharp, sometimes fantastic, curves. 
Bounded by great lakes on the north and east, and exposed 
on the south and north-west to the warm, moist winds of trop¬ 
ical seas in summer, and to the cold, dry winds of sub-arctic 
regions in winter, the scientific climatologist might with cer¬ 
tainty predict an extensive range of temperature for the year 
between the maximum and minimum of summer and winter, 
respectively, as also between the mean or average of one and 
the other of these extreme seasons. And the results of nu¬ 
merous actual observations, extending through a series of years, 
show that the causes named do really produce those anticipated 
contrasts and local peculiarities, and to a very remarkable ex¬ 
tent modify the climate of the State. 
A reference to the map will show this at a glance, for the 
isothermal lines thereon, instead of varying slightly in their 
direction from a course due east and west, cut the parallels of 
latitude at various angles, from ten to ninety degrees. The 
small dimensions of the map limited the location of the iso¬ 
thermals to about the number there shown, and we have ac¬ 
cordingly drawn merely the means for the year, and for the 
four seasons, at intervals of five degrees, together with the 
means for the two extreme months of spring and autumn, re¬ 
spectively. Future observations may show these lines to be 
slightly out ot true position, but in locating them we have used 
