Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1914-01-29
WAlMS of THE AIR
Curious and Rapid Changes In
the Velocity of the Wind.

Since man has provided himself with
wings he has learned more astonishing
! things about the air than were dream
ed of I'm bis old. philosophy. He has
had TO learn them in order to make
travelling safe on his new aerial high
way. The wind was almost complete
| mystery until neronauts begun to make
close acquaintance with It's strange
moods and vagaries. The stnrtling OK
| 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:
II two thermometers (wind measur
ers) are placed side by side about sew
enry-two feet above the ground when
wind of from thirty-three to forty
eight feet per second is blowing the
most remarkable differences in the We
locity OF the wind are observed. If the
thermometers are only ten inches apart
both usually show nearly the same
wind velocity. but IL the distance be-
tween them is increased to about thir
ty-two inches one will sometimes show
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-four feet. the
usual length of an aeroplane. the diff
ferences in the velocity of the wind
shown hp fhnnr
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
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 I'm this capricious
fashion at places a few feet or few
yards apart. but It varies with equal
violence and suddenness ut the same
point. rs is proved by fixing a single
thermometer at height of seventy
five or eighty feet above the ground
and observing the successive changes
in its indications of velocity. Thus il
has been found that wind whose av.
erage velocity was about thirty-eight
feet per second maintained that We.
.ocity for as much as ten successive
seconds and then in a second and a
half dropped to less than fourteen feet
per second. which ii maintained during |
two seconds. after which in the course
OF half a second it sprang up to a 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 i'm three-quarters of a second |
from twenty-six and one-quarter feet /
10 fifty-seven and onehalf feet per see. I
ond
Considering these facts. II is no won
der that aviators meet with strange /
accidents by running into what they
call "holes in tile 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
D the navigator of the air il becomes
sometimes n very demon, or q legion
If demons. whose eccentric gambnlings
ire us uncomfortable as they are unex.
1ected.
1t took thousands OF years for sea
men to learn how to face with un.
hearts the vaCaries. of the
,cean waves and currents and for
to devise vessels that
.ould defy them. but II seems likely
hat we in n few decades shall have
mastered tie caprices of the atmos-
'here and have produced airships that
will safely ride the widest wind.
1t is the advance of science that has
iven us the great advantage which We
POSSESS over our predecessors in over
oming natures obstacles. but in
of knowledge would not have
erve1 us If there had been decrease
+ courage That there has been no
uch decrease is proved every day by
he daring feats of avintors.-Garrett
,. ServiSs in New York Journal.