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The history of Columbia County, Wisconsin, containing an account of its settlement, growth, development and resources; an extensive and minute sketch of its cities, towns and villages--their improvements, industries, manufactories, churches, schools and societies; its war record, biographical sketches, portraits of prominent men and early settlers; the whole preceded by a history of Wisconsin, statistics of the state, and an abstract of its laws and constitution and of the constitution of the United States

Oldenhage, H. H.
Climatology of Wisconsin,   pp. [121]-128 PDF (3.9 MB)

Page 122

      Among local influences which modify climate, the nature of the soil
is one of the.most
 important. As water absorbs much heat, wet, marshy ground usually lowers
the mean tempera-
 ture. A sandy waste presents the greatest extremes. The extremes of temperature
are also modi-
 fied by extensive forests, which prevent the soil from being as much warmed
and cooled as it
 would be if bare. Evaporation goes on more slowly under the trees, since
the soil is screened
 from the sun. And as the air among the trees is little agitated by the wind,
the vapor is left to
 accumulate, and hence the humidity of the air is increased. Climate is modified
in a similar man-
 ner by lakes and other large surfaces of water. During summer the water
cools the air and
 reduces the-temperature of the locality. In winter, on the other hand, the
opposite effect is pro-
 duced. The surface water which is cooled sinks to lower levels; the warmer
water rising to the
 surface, radiates heat into the air and thus raises the temperature of the
neighboring region.
 This influence is well illustrated, on a great scale, in our own state by
Lake Michigan.
     It is, lastly, of importance whether a given tract of country is diversified
by hills, valleys and
 mountains. Winds with their warm vapor strike the sides of mountains and
are forced up into
 higher levels of the atmosphere, where the vapor is condensed into clouds.
Air coming in con-
 tact, during the night or in winter, with the cooled declivities of hills
and rising grounds becomes
 cooled and consequently denser and sinks to the low-lying grounds, displacing
the warmer and
 lighter air. Hence, frosts often occur at these places, when no trace of
them can be found at
 higher levels. For the same reason the cold of winter is generally more
intense in ravines and
 valleys than on hill tops and high grounds, the valleys being a receptacle
for the cold-air currents
 which descend from all sides. These currents give rise to gusts and blasts
of cold wind, which
 are simply the out-rush of cold air from such basins. This is a subje~ct
of great practical impor-
 tance to fruit-growers.
     In order to understand the principal features of the climate of Wisconsin,
and the conditions
 on which these depend, it is necessary to consider the general climatology
of the eastern United
 States. The chief characteristic of this area as a whole is, that ,t is
subject to great extremes-to
 all those variations of temperature which prevail from the tropical to the
Arctic regions. This
 is principally due to the topographical conditions of our continent. The
Rocky mountains con-
 densing the moisture of the warm winds from the Pacific and preventing them
from reaching far
 inland,, separate the climate of the Mississippi valley widely from that
of the Pacific slope. Between
 the Gulf of Mexico and the Arctic sea there is no elevation to exceed 2,ooo
feet to arrest the
 flow of the hot southerly winds of summer, or the cold northerly winds of
winter. From this
 results a variation of temperature hardly equaled in any part of the world.
     In determining the climates of the United States, western Europe is
usually taken as the
basis of comparison. The contrast between these regions is indeed very great.
New York is in
the same latitude with Madrid, Naples and Constantinople. Quebec is not so
far north as Paris.
London and Labrador are equi-distant from the equator ; but while England,
with her mild, moist
climate, produces an abundance of vegetation, in Labrador all cultivation
ceases. In the latitude
of Stockholm and St. Petersburg, at the 6oth parallel, we find in eastern
North America vast ice-
fields which seldom melt. The moist and equable climate of western Europe
in high latitudes
is due tolthe Gulf Stream and-the southwest winds of the Atlantic, which
sprea@l their warmth
and moisture over the western coast. Comparison, however, shows.that the
climate of the Pacific
coast of North America is quite as mild as that of western Europe; and this
is due to the same
kind of influences, namely, to the warm, moist winds and the currents of
the Pacific. And to con-
tinue the comparisoli still further, in proceeding on both continents from
west to east, or froM'
ocean into the interior, we find a general resemblance of climatic conditions,
modified greatly, it true, by local influences.

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