The Caucasian. (Clinton, N.C.) 188?-1913, 1912-09-26
Rivers In
the Air

Did you know tAsr. -, ,.
The atmosphere !uss a. rraI
snt a are the waterfalls ,ou
often viewed with atrirs,,a.
light because OF their na,u-.I -
In the famed Yosemite vale,
Interesting feature L. 10 -. -
perhs~<. its Winds
The winds there are nslA,
than light Zephyrs. moody a..
cious 20 the ordinary tours, -. =
rightly understood. one o, ,As.
Of the valley. These tn,eres,,,r -
are told by Prof r + Ma;,A.. :,
United States geological Earrsr !, =,
Sierra Club Bulletin.
In no other place In the su,j.e -,
perhaps, are the air currents No.,
tematic and regular than in ,As -
lite valley, he says. In the IN, 49,.
the sun naturally heats the -.
more rapidly than IL does the air =.
every hillside basking in the s., ).
comes a heat radiator and g-aan,r,
warns the air above ii, so thai Ia -.
becoming lighter. begins to r1ss
But under those conditions TIE -,
does not rise vertically because ;hes.,
directly over IL is still cool apa !,
pressing downward. Therefore. up y,
sides of the warm slope the heated =.
makes its way. That In why the la,
list making his way up the mogn,as
slope with the sun on his hack ara,
his own dust travelling upward vlA
him in a choking cloud.
But on coming down the same tzg
when the face OF the slope Is In u.
shadow the dust ever desoends vra
the traveller in the same irrltatlfr
cloud. When the face OF the mountlr
is in the shade the air is cooling 'roa
the face of the slope and Is pressing
it's way down into the valley
Just as soon as the sun leaves tss
slope of the mountain, the earth -
gins to lose its heat by radiation. tha
in a very short time is really c0oss
than the air. The layer Of air EsIi
the face of the hillside chllls ~ O.
tact with the earth, and becoming haF
Ter as ii condenses, begias TO F-,R
down along the slope. Thus there s.
normally, the warm updraft On lie
sunny slope and the cold dowu1rai,@
the side in the shadow. In a Winds
region like the Yosemite, with iu@
cliff topography, these upward 81
d<x I'D nj
interrupted. On every sunny ssp
bold cliffs create shadows and cC1se
quently there are downward air c.
rents Of local breezes daily al reeE1
hours, as the shadows come and 60
I Glacier Point Is one place In paris
ular in which Professor Matthes san
this shadowy effect on the air curTefa
may readily be tested by casting snaA
bits of paper into the air. As The al
ernoon wears on and the shadows
the valley gather, the cold draft 10 ne
hills pours downward. forming the w
ley Ike q great river, and flowing O.
TO the plains below. Every side eT
yon and valley sends its reinforce
ments, Hike the tributaries OF gre1
river, to this general air current sos'
ing onward to the plain.
With the return Of the mornins 81
the earth 1t the tops Of the niih
warmed and the downward current '
the air ID suspended. The updran 500
begins q the sun shines into TIE
legs. The air currents are 30 res'~
that they may almost be timed
Few realize, says the author Of =.
paper, that II n on these reversins -
currents that one of the chief 81
lions Of the Yosemite depends 1T
lake, to be viewed at its best m
seen IN the early dawn. when the |"
neetions are most perfect
The lake Is stiIlest and It's SUITE.
most mirror-like when the colo
currents have ceased and the up'1
day currents OF air have not ye.
gun. Yet unless one Is punctnA
will miss the chief beauty OF the
for this perfect stiffness is as of'e'
the turn of the tide
In the evening and during the n'.s. -.
when the downdraft Of air from - !,
mountain sides Is strong. the stream :
cool air pressing down the siope -.
ges over cliffs Just as water y
to fall from similar heights. Va s-ns
the Yosemite falls or the NeV~l~ -,
trails, this air-faH curiosity Is To-
encountered In the evening.
During the daytime, on the % .ss
hand, the air rises vertically aiOAs -
cliffs and up into the hanging 'A-. -.
! taking part OF the spray from 'Ns ,bs
along with it 4 pretty example y t.a
! air carrying the spray from - vsa
upward may be seen at bEiD1, ,ay.
falls, where two little combs o. -
one on each side OF the stream;
fly curve upward over the tr III
As soon as the sun Is on