, 1889-09-26
PRgpARINe WEATHER RgPoRrs.
How "oId Prob" Makes His Forecasts of
Atmospheric Changes.

went up to the signal office the other
day to ask Gen. A. w. Greedy how he
and his fellow conspirators regulated the
weather of which this season has been
so prolific. 1 found the lucky and
plucky Attic explorer at his desk, robed
in a full suit of white flannel over a
checked lannel shirt;a dream of COM
fort and a very delightful antithesis to
the young lieutenant who, six years ago.
was waiting for death at Camp Sabine.
What is the percentage of right esti-
mates of this bureau7"
ut averages something over so per
cent. You would not think so to read
the papers. But the fact is, when prob
abilities prove to be correct newspapers
do not notice it.; they only have some
thing to say when we miss fire. A New
England daily paper said last Wednes-
day that our estimates for that section
hadn't been right in a week l sent
the statement to my expert, whose bust
ness is verifcation, and he went over the
facts and figures, and found that 81 per
cent of the predictions of the bureau
for the period and section had peer cor
rect"
"How do you make your estimate for
to-morrow's weather, generalr'
81 could give you a statement of 1t,
but l had better refer you to Capt. Dun
woody, the officer who has had predic-
tions in charge for many years. He is
at this III making up his weather
sheet for tomorrow"
Gen. Greedy kindfymxaAxed with me
out of his handsome room into the low
adjoining, where Capt. II. II. C.
Dunwoody, of the Fourth artillery,
makes his working headquarters, and
there / was presented to him-a soldier
ly built officer, with n military bearing
and alert face, his short hair turning
gray as he talks about the weather.
Here they are" he said, touching
with his hand n bushel of mussed up
telegraph dispatches, "the data on which
we make computations. These were re-
ceived at 8 o'clock this morning, Wash
ington time, from our 100 stations in al
parts of tho country. These all reached
us within thirty minutes this morning.
Similar dispatches come three times a
day"
They tell you" 1 ventured, "what
the weather has been and is. What the
BtbGlC al W A1ON . INV 1Ou bhCno
what the weather is going to be. Or
perhaps l should not use the word
'guessg'"
Certainly you should" answered
Capt. Dunwoody. "'Guess' is a good
word. Much of our prediction is neces-
sarily conjecture-that is, it is I'm at
tempt to solve a problem when some of
the important elements are missing.
These dispatches tell us five important
things about the prevailing atmospheric
conditions in $50 places: 1. the measure
of the barometer; 2, the thermometer;
3, tho force and direction of the wind;
4, the character of the clouds; 8, mois-
ture, or hydrometic conditions. Here
we have the weight of the atmosphere,
the heat, the wind, the clouds, the rain
in 100 places-an important basis for
n judgment. When we get these dis
patches we take five blank maps of the
United States and Canada and outline
the five conditions-heat, rainfall, etc,
so that the state of the Union, so to
speak, becomes pictorial. Now we ave
something for any analytical mind to
work on-the weather In every terri
tory. Here are the maps for today.
Isotherms are drawn through all the
places of equal temperature; isobars over
all points of like barometric pressure,
and SO on.
"You see there is n circle marked
frost in the cranberry region of upper
Wisconsin. The fact that frost is there
today comes to us by telegraph. But /
predicted it yesterday morning and sent
warning to the cranberry region to
look out suppose some of them did.
The day before yesterday frost was re-
ported in Pembina, northern Minnesota.
High areas generally move east to south
east; and l thought 1t safe to predict that
this cold wave would go to the cram
berry region. 1t did and it reached
there in just twenty-four hours, as l an
ticipated. The trouble is that not one
half of the farmers got the warning in
time. Some years since l sent a dispatch
to Madison, Wis, warning them that
there would be frost the second day af-
ter. The editor who handled it stuck it
in a drawer and there it slept. / after
ward heard Gen. Rusk, now commission
er of agriculture, say TO the Wise onsin
state grange that If an organization had
existed to distribute that prediction it
would have saved $1,000 to the farm
ers of the state. The great need OF the
service today is distribution. Emphasize
that, please. Some provision should be
made by which the important probabili-
ties can speedily get to the farmers for
whose protection they are chiefly use
full"
"How long are your predictions"
"Twenty-four hours; sometimes thirty
six. Occasionally, when indications are
very clear, forty-eight. We shall extend
Al. .;... - l;t+la ,axt ,-aor IUaatbnr