The Bossier banner. [volume] (Bellevue, Bossier Parish, La.) 1859-1952, 1914-01-01
WH|MS OF THE AIR
Curious and Rapid Changes In
the Velocity of the Wind.
HOLES IN THE ATMOSPHERE.

0OLEo tN bHE n tMOSF 0En6.
These Danger Spots, From the Avia.
tors Viewpoint, Are Born Of tho Al.
most instantaneous Variations In tho
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 ia his 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 aerouuuts began to make
close acquaintance with its strange
moods and vasaries 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
Aeroteclnic institute of the University
Of Paris:
II two thermometers twind measur.
ers, are placed side by side about sew
enty-two feet above the ground when q
wind of from thirty three to forty
eight feet per second is blowing the
,mosi remarkable differences In the, ve-
iOcity of the wind are observed. Ii the
| thermometers are only ten inches apart
both usually show nearly the same
wind Velocity. but Ii 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 by them are occasionally enor.
nous. but Of very brief duration This
must clearly produce racking effect
upon an aeroplane. which may he dis.
astrous. for one end Of II may for q
second or so experience a resistance
double that felt Mt the other end
But this Is by no means all! Not only
does the wind vary In this rapricious
fashion at places few feet or few
yards apart. but 1t varies with equal
violence and suddenness at the same
point. as is proved by fixing d single
thermometer at height of seventy.
Ave or eighty feet above the ground
and observing the successive. changes
In its indications Of velocity Thus II
has been found that a wind whose av.
erage velocity was about thirty-eight
feet per second maintained that We
!. lncity for as much as ten successive
seconds and then In u second aud O
half dropped to less than fourteen feet
per secnnd. which II maintained during
two seconds after which In the cours.
Of half a second II sprang uI to We
locity OF City feet per second: 1t main
tained the last mentioned velocity fOl
only n single sccund
In another case the velocity Of the
wind rose In three-uuarters uf a secon(
. from twenty-six and one quarter fee
to fifty seven aud Que half feet per sec
ond
Considering these facts. II Is no won
der that ayiatUrs u,eet with strang
accidents by running into what the!
call "holes in the air." for the sustain
Ing force of the air, On account Of tn
sudden variations Of the wind ma.
almost instantly lose half it's value ant
. then with equal suddenness recover. o
more than recover. it's former power
Such things ennt,ie any one to under
stand the peculiar periis that the avia
tor has to fnce Even ordinary mortal
know that the wind ~ capricious. bu
, to the navigator of the air 1t become
sometimes n very demon. or legio
Of demons, whose eccentric gaInboling
] are as uncomfortable as they are unea
: pected.
. II took thousands Of years for set
: tnrn to learn how to face with ur
e rincling hearts the vagaries Of th
+ ocean waves and currents aud fo
0 si,iplmilders to devise vessels tina
: could defy them. but II seems likel
:. that we In few decades shall hav
mastered the caprices Of tht, atmo.
!. I,llere and have produced a!rships tina
). will safely ride the widest wini
J. 1t is the advance of science that hu
J. given US the great advantage which "
: possess over our predecessors in owe
e coming natures obstacles. but II
, increase of knowledge would not hav
served ns If there had been decreas
Of courage That there has been r
such decrease is proved every day b
r the during feats Of nviators.-Garre
4 r. Serviss in New York Journal
t.