Warren sheaf. [volume] (Warren, Marshall County, Minn.) 1880-current, 1913-12-24
WH|N Ms Of The I !: AIR n !
Curious and Rapid Changes In
the Velocity Of the Wind. s
HOLES IN THE ATMOSPHERE.

HOLES IN THE ATMOSPHERE.
Those Danger Spots, From the Avia-
tors Viewpoint, Are Born Of tho A..
most instanta nsous Variations In the
Force Of the Aerial Currents.
:, Since man has provided himself with
wings he has learned more astonishing
things about the air than were dream
ed OF in his old philosophyr He has
had to learn them in order to make
travelling safeton his new aerial high
way. The wind was almost a complete
mystery until aeronauts began to make
close acquaintance with its strange
moods and vagaries. The startling ex-
periences Of aviators have stimulated
the anemometrists-i. e.. the wind
measurers-to fresh Investigations,
which have had surprising results.
Consider, for instance, these, things
which have been found out by the
Aerotechnic institute of the University
Of Paris:
If two thermometers wind measur-
ers) are placed side by side about sew
enty-two feet above the ground when a
wind Of from thirty-three to forty
eight feet per second is blowing the
most remarkable differences in the We
l0city Of the wind are observed. If the
thermometers are only ten inches apart
both usually show nearly the same
wind velocity. but If the distance be-
tween them is increased to about thir-
ty-two inches one will sometimes show
q wind velocity of ten feet per second
more rapid than that shown by the
other. But this difference lasts only
for an instant. If the distance be-
tween the thermometers is increased to
tWenty-three or twenty-fou feet, the
usual length Of an aeroplane the diff
terences in the velocity of the wind
shown by them are occasionally enor-
nous, but of very brief Duration This
must clearly produce a racking effect
upon an aeroplane. which may be dis
astrous. for one end of it may for a
second or so experience a resistance
double that felt at the other end.
But this Is by no means all. Not only
does the wind vary in this capricious
fashion at places few feet or a few
yards apart: but it varies with equal
violence and suddenness at the same
point, as Is proved by fixing single
thermometer at a height OF Seventy
ire or eighty feet above the ground
and observing the successive changes
In it's indications OF velocity. Thus it
has been found that wind whose av-
erage velocity was about thirty-eigh,
feet per second maintained that We
locity for as much as ten successive
seconds and then in a second and
half dropped to less than fourteen feet
per second, which it maintained during
two seconds after which in the course
of half second It sprang up to We
locity Of fifty feet per second! 1t main
tanned the last mentioned velocity for
only single second.
In another case the velocity of the
wind rose in three-quarters of a second
from twenty-s1x and one-Quarter feet
to fifty seven and One-half feet per Sec
ond
Considering these facts, it Is no Won
der that aviators meet with strange
accidents by running into what they
call "holes in the air." for the sustain
ing force Of the air, on account Of the
sudden variations of the wind, may
almost instantly lose half its value and
then with equal suddenness recover, or
more than recover. its former power
Such things enable any one to under
stand the peculiar perils that the avia-
tor has to face. Even ordinary mortals
know that the wind is capricious, but
to the navigator Of the air 1t becomes
s0fnecimes very demon. or legion
~ ~ demons, whose eccentric gambolings
are as uncomfortable as they are unex>
pected.
It took thousands Of years for sea
men to learn how to face with un-
finch1ng hearts the vagaries Of the
ocean waves and currents and for
shipbuilders to devise vessels that
could defy them. but it seems likely
that we in few decades shall have
mastered the caprices of the atmos-
phere and have produced airships that
will safely ride the widest wind
It is the advance Of science that has
given US the great advantage which we
possess over our predecessors in over
coming natures obstacles. but in
increase of knowledge would not have
served US if there had been decrease
of courage. That there has been no
such decrease is proved every day by
the daring feats of aviators.-Garrett
P. Serviss in New York Journal
One Way to Clean Windows.
There are so many best ways to
clean windows that one hesitates to
offer her method unless very sure it Is