Belmont chronicle. [volume] (St. Clairsville, Ohio) 1855-1973, 1878-07-18
How the Weather is Foretold.

am mblt1OuSly prOpheSlod WnOle year
of cold and heat, wet and dry, dividing
up the kinds of weather impartially, if
not always correctly.
But the almanac, good as it was then,
and the weather-Wise farmer, correct
rs they sometimes might have been,
were not always able to impart exact
information to the country; and they
have been thrown quite into the shade
of late, by one who is popularity known
under the somewhat disrespectful IL
tie of 'Old Prob or odd Probabilities
He has become the Herald OF the
Weather to the sailor, near the rocky,
dangerous coasts; to the farmer, watch
ing his crops, and waiting for good
days to store them; to the traveller,
anxious to pursue his journey under
the fair skies; and to the girls and
boys who want to know, before they
start to the woods for d picnic, what
are the probabilities as to rain.
Every one who reads the daily pa
pers is familiar with the Weather
Record issued by the War Depart
ment Office of the Chief Signal Officer
Washington. These reports give, first,
general statement OF what the wealth.
er has been, for the past twenty-fours,
all over the country. from Maine to
California, and from the Lakes to the
South Atlantic States; md then the
Probabilities, or Indir"tions,' for the
next twenty-four hours, over this same
broad territory. The aI,nrIal reports
of the Chief Signal Officer show that in
only comparatively few instances do
these daily predictions fail of fulfill
nent.
The reason these prophecies are so
true is a simple and yet wonderful
one. The weather itself tells the OBJ
server what 1t is going to do,sometime
in advance, and the telegraph sends
the news all over the country, from
the central signal Office at Washington.
We shall see, presently, how the
weather interprets itself 10 old Prob
Abilities Although 1t has proved
such fruitful subject Of discourse in
all ages, yet am afraid many people
who pass remarks upon it, do not real
ly think what the weather Is made Of.
Let Us examine Its different elements.
The atmosphere has weight, just ss
water or any other fluid, although 1t
seems to be perfectly bOdiless. We
must comprehend that the transparent,
invisible air Is pressing inward toward
the centre OF the earth. This pressure
varies according 10 the state of the
weather, and the changes are indica-
ted by an instrument called barOm-
eter. Generally speaking, the falling
Of the mercury In the tube of the bar
ometer indicates rain, and its rise her
aids clear weather. Sometimes the
rise Is followed by cold winds, frost and
ice. What these changes really ind1-
cate, Can be determined only by COM
pairing the barometic changes, at Ger.
tain hours, In number OF places very
far apart. This is done by the Signal
Service. Observations are made at
about one hundred and forty stations,
in different portions Of the country, at
given hours, and the results are tele-
graphed at once to Washington, where
our faithful weather clerk receives
them, reasoning out from the 'proba-
bilities' which he publishes three
times in tWenty-fOur hours.
But the atmosphere varies not only
in weight, but also In temperature.
The thermometer tells US OF such
changes.
Besides this, the air contains great
amount of moisture, and it shows as
much variation in this characteristic as
in the others. For the purpose OF
making known the changes in the
atmosphere, an instrument has been
invented called 'wet-bulb' thermom-
eter.
We are thus enabled to ascertain the
weight or pressure, the temperature,
and the wetness of the air, and now it
only remains for US to measure the
force, and point out the direction, of
the wind. This is done by the famili'
ar weather-vane, and the anemometer
is an instrument which indicates the
velocity of the wind. :,
1t is by right understanding OF all
these instruments that the signal SER
vice officer is enabled to tell what the
weather says of itself; for they are the
pens with which the weather writes
out the facts from which the officer
makes up his reports for the benefit oil
all concerned. Thus, however wildly
and blindly the storm may seem to
come, it sends messengers telling just
where it arose, what course it will
take, and how far it will extend. But
it tells its secrets to those only who
pay strict attentiOn.-James Ii. Flint,
st. Nicholas for July.