Juniata sentinel and Republican. [volume] (Mifflintown, Juniata County, Pa.) 1873-1955, 1879-11-26
Tic Indian Summer.

Indian summer Is certainly a very char
acteristic and periodical phenomenon in ali
these high American latitudes, as it is in
Central Europe, though probably in q less
marked degree, and there are reasons for
believing that it exerts its softening influ-
ences upto the Arctic circle, tempering the
first waves of winter cold that descends
upon Arctic America. But it does not ap-
pear to lavish its charms on the Tar South
OF lower lautudes Of the United States,
where. indeed, they are not much needed.
Although it is often prolonged into Decem-
Der when calm, hazy atmosphere fills the
sky, through which the sun, shorn Of his
strength, sinks day after day, like globe
OF fire. The Indian Summer at the PrOvin-
cial Observatory in Toronto, Canada, has
been occasionally recorded as early rs the
9th Of October. The average date Of its
distinct appearance there. deducted from
. fourteen years observation, is October %
Search for explanation OF this phenomenon
las no; escaped scientific investigation. As
either pole Of the earth is turned around
. the sun after the vcrnai equinox, and solar
effect increases in the direction Of that pole
until q tLaw Of the winters accumulated
. ice GETS in, when an interval Of cold occurs,
caused by the rapid absorption Of solar heat,
and thus the frequent ''cOld spells of the
I later spring months is often accounted for.
When, on the contrary, either pole is turn
ed away from the sun after the autUmnal
equinox, the converse process takes place;
the higher parts OF the continent are chilled
and the ensuing condensation Of the vapor
in the air li6eTatIng its heat, raises the
temperature. and thus an interval of com.
parativcly warm we.iher or second sum-
mer follows. This simple explanation Of
Indian summer first advanced by Admiral
Fitzr0y, is corr0boratod by the fact that the
increase Of temperature attending il is the
greatest in the highest la;itudes Of Ameri-
ca, where il is described IS sometimes sop
prcssive'-just where Of course the earth's
crust in October is undergoing the most
rapid Refrigeration, where ice is forming
and consequently the heat of the cOndensa-
tion is most freely liberated from the lower
atmospheric strata. The heat generated by
condensation is familiar to all who reflect on
their sensations when = shower is being
formed in the clouds By this process on Il
SultTy day. Were it not for the cOmpara-
tive drynesS Of the ar in the interior of the
continent, or rather If it were moist enough
at this season, the cooling of the earth
would produce clouds and rain, instead of
the ''dry fog as Indian Summer is tech
nically called The phenomenon in ques-
tion has. it would appear, been more the
theme Of poets than Of physicists. But of
minor importance in a meteorological point
of view as it may seem, its further inyes-
tigation might furnish a clue to some prob
lens of our climate which are yet unsOlyed.
The fine particles Of dust which often fall
on vessels in the open Atlantic, near the
Cape Verde Islands, when subjected to the
microscope, have proved tallies on the
winds, serving to fix the direcrion of the
''trade winds from the African coast, and
thus clear up one of the questions of ocean
meteorology. Many no less striking exam
piles Of seemingly unimportant phenomena
leading to important discoveries abound in
the history of science.