The true northerner. [volume] (Paw Paw, Mich.) 1855-1920, 1871-07-14
THE GREAT LAKES.
The Extent Of these Island Oceans-The
Effect they have ON the Climate-Why
Michigan IL Good Fruit state.

The current number of Harper'S Mag
a=ine has an interesting illustrated arti-
Gle by Prof. Winchell on the "Ciimate
of the Lake Regions" From it we ex-
tract the following
The climatic influences of vast bodies
of salt water, like the Atlantic and
Pacific oceans, have long been under.
stood. The effect of small inland bodies
of fresh water in averting early au'
tumnal frosts has also been generally
remarked. But, as before intimated,
meteorologists do not seem to have OBJ
served, till recently, that great lakes,
like Lake Michigan or Lake Superior,
exert an influence in DETECTING the
isothermal lines which is quite COM
parable with that exerted by the great
oceans themselves.
These lakes, in truth, are no incon-
siderable representatives of the ocean.
Lake Superior is AGO miles long and 100
broad. with mean depth of 9SS feet.
1t has superficial area of 81, 900 square
miles. The State of Massachusetts,
might stretch herself out at full length
and battle in its waters. Even then
there would be room enough for Rhode
Island at her feet and Connecticut at
her head, with Vermont stretched along
her right and New Hampshire on her
left. You may take all New England,
excepting Maine, and hide it bodily be-
meath the waters of this single lake.
Lake Michigan is 500 miles long and
los broad, with a mean depth of 900
feet and superficial area of 10000
square miles. You could sink in this
lake three States of New Jersey, Della
ware and Maryland. Lake Huron, with
equal to that of Lake Superior, has a
mean depth of 800 feet, superficial
extent equal to that of Lake Michigan,
and would swallow up the kingdom of
Denmark, including the duchies.
You may embark on a sea-worthy
steamer at Chicago and travel for thirty
hours without sight of land; and,
after having passed the Straits of
Mackinac and entered Lake Superior,
you may steam for two days more with
out reaching Superior City or Duluth.
The voyage from Buffalo to Chicago
around the lakes Is thousand miles ;
from Buffalo to Duluth is eleven hun
dred miles, or three-fifths the distance
from Newfoundland to Ireland
The majesty of the tempest is little
less in the lakes than on the Atlantic,
and the low perpetual moan of the
breaking waves along the beach trans
ports the imaginative listener to Long
Branch or Nahant. During a summer
day they breathe, like the ocean, a
cooling atmosphere on every shore,
while at night the direction of the
breeze is frequently reversed. These
are our interior land and sea breezes.
To complete the analogy, our great in
land seas exhibit the fluctuations of a
diminutive but genuine lunar tide.
1t is impossible that such enormous
masses of water should be materially
elevated above the mean temperature
of the year by three months of summer
weather, or depressed materially below
it by three months of winter. The
land surfaces in the same ATTITUDES at
tain far greater extremes of cold and
heat than the lakes Two reasons exist
for this: First, watery surfaces absorb
and radiate more slowly and secondly,
the continued stirring of the waters by
the winds mixes the surface tempera.
ture through depth of several hun.
effect is confined tosa superficial zone OF
about seventy to ninety feet. The nor.
NAL mean annual temperature Of the
land in the neighborhood Of milwaukee,
is A degrees, and this should be about
the mean temperature of the water OF
Lake Michigan. In summer the Mil
waukee mean rises to 81 degrees. while
in winter it sinks TO % degrees. The
water Of the lake, meanwhile, rises in
summer only to 40 degrees. Winds
from the lake, therefore, partaking
largely of the temperature of the water
must exert material influence in
equalizing the land temperatures OF
summer and winter. Still more, in
cases of extreme weather, when the
land temperature rises to % degrees, OF
sinks to SO degrees below zero, must the
ameliorating influence of such a vast
body of water, holding itself steadily al
somewhat uniform temperature, be
most conspicuously and most benef
Gently experienced.
There is one cause of the mild tenn
perature of deep lake waters during tn,
cold season, which probably has beer
very little considered. Lakes Michigan
and Superior are nearly a thousand fee
in depth. They reach down toward the
internal fires, distance which, i
measured through the solid crust of the
EARTH would bring us very consider
able increase of warmth. Upon tn,
land the influence Of climatic changes
: does not extend, on the average, to &
greater depth than eighty feet. Be
meath this we experience an increase o
, temperature amounting to one degre,
for every forty-five feet of descent. Ac
cording to this law the terrestrial tenn
perature at the bottom of Lake Michi
gan should be increased eighteen de
grees. Were there no mingling of tn,
deeper and shallower strata of waite
. this increase would exist. This amour
t of heat, nevertheless-with some abate
4. ment to which it is not necessary t.
, refer-distributed through the entir,
depth of the water, must produce NJ
, inconsiderable elevation Of temperatur,
in the general mass.