Sacramento daily record-union. [volume] (Sacramento [Calif.]) 1875-1891, 1884-01-01
METEOROLOGICAL.
INTERESTING DATA coNcERNIEG EVER
FAMILIAR SUBJECTS.
Curvatures in Isothermal Lines-Tempera-
ture of Air and Earth-Causes Pro-
ducing Dew, Frost, Fog, Etc.

Written and compiled by Sergeant James A. Bar
wick, Signal Corps, U. S. A, for the RECORD
UNION
Upon the subject of temperature it may
be said that the isothermsl, or heat line,
having mean temperature of 60 degrees,
passes through Sacramento, Cal; Memphis,
Tenn; Chapel Hill, N. c.; Norfolk, Va;
through the north of Spain, Rome in Italy,
a little south of Constantinople, near the
south end of the Caspian Sea, and through
Shanghai in China. This line shows that
places having the same mean temperature
as Sacramento are situated, speaking by
the parallel rule, both north and south OF
this city. This shows the fact that there
are places on the same parallel with this
city that are both colder and warmer than
at this point. 1t is universal law, and
known by experience, that as we proceed
from the equator toward either pole, the
temperature decreases. Were there no
local influences, the decrease would CORE
spond to each degree of latitude, thereby
making each isothermal, or heat line, run
along each parallel of latitude, but this,
we see, is not true, and this accounts for
for places on the same parall-l, and this
difference is
DUE TO LOCAL CAUSES.
We find the isothermal line, with a mean
temperature of so degrees, passes through
Puget Sound, on the Oregon coast through
Burlington, Ia; Pittsburg, Pa; New Ha-
ven, Conn; Dublin, Brussels, Vienna and
north of Pekin, China. The mean tenn
perature of the eastern or European side
of the Atlantic Ocean is much warmer than
that of the western or American side upon
the same parallel Of latitude. The mean
temperature of New York is absut the
same as Dublin, although the latter place
is Is degrees north of New York. Near
Lake Superior, in lat tude 80 degrees, we
find the same mean temperature as at the
North Cape, in latitude y degrees. This
high temperature of the European coast is
due to the high temperature of the North
Atlantic Ocean, combined with the preva.
lent westerly winds. By means of the
Gulf Stream. the waters of the equatorial
regions are conveyed into the North AT.
lantic and portion Of this warm current
extends northwArd between Iceland and
che British Islands, and continues TO the
Arctic Ocean. The temperature of the
North Atlantic is thus raised much above
what is due to It's latitude, and since
throughout the middle ATTITUDES the
prevalent winds are from the west, this
heat of the ocean lie communicated to places
on the eastern side Of the Atlantic, but not
TO those on the western side. The currents
of the Pacific Ocean produce an effect sim.
liar to the currents of the Atlantic, and
there is a corresponding difference between
the temperature Of places on opposite
sides of the Pacific Ocean, and consequently
a marked difference between the tempera.
ture of places on the Atlantic and Pacific
coasts OF North America, although situated
on the same parallel of latitude. The
isothermal, or heat line, of 80 degrees, is
found 10 degrees further nGrth on the Pa
cite coast than on the Atlantic coast.
Sitka, in latitude 81 degrees, has about the
same mean temperature as Eastport, Me-,
in latitude Il. The highest temperature
in open air ever recorded by thermom.
eter was on the Sahara desert, where it
reached 1913 degrees, and a thermometer
placed inside of a blackened box and COW
cred with glass has been known to rise to
24S degrees. The lowest temperature OBJ
served has been, Of course, in the Polar re-
gions. a temperature OF rs degrees below
zero was marked at Jakutzk, Siberia, and
il the United St4tss 80 degrees below zero
has been recorded in Montana The high
est recorded in the United States was l2l
degrees, at Fort Miller, California
TIE TEMPERATURES OF THE EARTH
Has been obtained at various depths, and
st a certain depth ia found to be unchange-
able, being the same in winter as in sum.
mer. This depth depends upon the ex-
IRENE range Of the temperature of the air.
In Europe it is from so to 100 feet. A
thermometer which has been kept for IS
years in the vaults of the Observatory at
Paris at the depth Of 81 feet below the
surface, has not varied more than half a
degree during the entire time. Below the
depth Of 100 feet we find an unavailable
Temperature throughout the year. Numer-
Gus observations have been made, and they
always indicate that the mean temperature
increases with the depth These observa.
lions have been extended to very great
depths by means of mines and artesian
wells. In Europe the average increase of
temperature deduced from mines and ar
tesisn wells IS one degree for descent Of
- feet In the United States there is an
increase of one degree for each - feet be-
II.
the earth at great depths increases at the
same rate as near the surface, at depth of
t~o miles the temperature must exceed
that OF boiling water, and at a depth of
less than one hundred miles the rocks
would be in a state Of fusion. We are thus
led to conclusion tLat with the exception
OF a comparatively thin crust upon the
surface, the entire mass of the earth is
probably II a state of igneous fusion. Vol
canoes are so numerous as TO indicate that
4 considerable portion OF the interior Of
the earth must be in such state. Near San
Francisco IS a spring which perpetually
emits boiling water and there is a similar
one near the eastern boundary OF Califor-
MIA. These springs probably rise from
great depths, and are proofs of the increas.
ing temperature of the earth as we de.
scend below the surface.
FORMATION OF CLOUDS.
The vapor generated at the surface of the
earth by the heat of the sun tends, by its
expansive force, to spread in oil directions,
but especially upward, and forms an at
mosphere of vapor whose density decreases
with the elevation. Since the temperature
OF the air sinks as we rise above the earth,
it may happen that at certain hight the
tension OF the vapor is greater than CORE
spends to the temperature which prevails
.. that elevation, IN which case a portion
OF the vapor viii be precipitated and form
a cloud. Eapor may also be transported
to great hight by the ascending currents
OF air caused by the heat Of the sun.
These currents oTdinar ly give rise to Gu
mulusclouds, and it frequently happens that
the sky though clear in the morning, is
filed with those clouds at noon. Any
cause which chills q humid air determines
the formation Of cloud. 4 cold wind pen
etrating = aumId air, or G warm and humid
wilma penetrating cola air, causes the
precipitation Of vapor and the formation Of
cloud. At tse close Of a warm day, espe.
clally after a rain, clouds are frequently
formed, which increase during the night,
and are dissipated the next day by the
effect OF the suns heat.