The Minneapolis journal. [volume] (Minneapolis, Minn.) 1888-1939, 1905-12-24

The revolution Of the cups is transmitted thru
a spindle and endless screw to the dial plates.
The mechanism of the spindle is SO arranged
that one hundred revolutions correspond to one
mile of wind movement At the end of each
mile of movement the instrument closes an
| electric circuit with the recording instrument
and the end Of the mile is indicated on sheet
prepared for the purpose.
| lower atmosphere there is tendency
for the warm air from the equatorial
regions to move towards temperate latl-
tudes and a counter-current, beginning
at about latitude 5O4degrees to 60 de-.
grees, moves at intermediate attitudes
into the temperate regions also. Near
~ everyone knows that the Japan cur
rent and the Gulf stream exist in the
ocean, but many probably do not un-
! derstand the forces which are employed
in their movement and direction. Sim
ilarly, you are asked to accept, with
out further explanation, these move.
ments that take place in the general
circulation of the atmosphere, first be-
cause they are known to continually
exist, and, second, because the explana--
ton is complex and would not mate
rally aid in the accomplishment of the
purpose for which these articles are
Intended. ..-.-4 H. 81.
i. !. + -...
The storm areas which move across
the country and give us the sudden
, and irregular changes that we expert
ence from day to day are products of
! the lower atmosphere. In other words,
t they are generated in the region lying
below the high eastward movement of
> the general circulation. Now, as there
t can be no absolute division between the
e two strata, their friction or intermin'
:, Cling has retarding effect on the ex'
! IRENE velocities that would otherwise
y develop in the upper stratum and ii
1 also gives an eastward movement tC
r the storm areas. The forces which de-
Q velop and maintain these storm areas
J are generated by the mixture Of the
; warm air from the south with the colo
e air from the north. The United States
= lies in the zone where this mixing take
place, and consequently experience
= greater ranges Of temperature AM
It much more sudden changes than usual,
is occur in the far north or in the tropi
n cal regions It is these storm area
ID with which we are mostly concerned
j. and we shall soon see that the force
m which cause them are not mysteriou
80 80 ones.
n :. + \
ly If you will take glass jar, fill
O. with water, and introduce bubble c
in air at the bottom Of the jar, you wi
observe that the air is forced upwar
OF thru the liquid to the surface, whe1
o. it escapes in medium Of its own de-
a. sity. This movement takes place vel
he rapidly and forcib1y, because Of tt
10 great difference in the density of IL
n, two substances. This is only anoth
OIL illustration Of the principle shown I
the hot-air balloon, but if you w
now introduce the air in continue
stream thru hose attached to the be
tom of the jar, you can maintain
Ia more or less perfect column Of air, e
~ the surface of the water. Now pla
ter ter so you will be able to trace the G,
ng rents generated by this action. Y
re- will observe that these particles mo
: IN Immediately around it, while fartf
Lei. .er away next to the walls of the jar,
he movement is downward. Near the 81
I'M face of the water the particles mo
emit outward from the central air colun
ace while near the bottom Of the jar tx
IN move in towards it again.
vas Now, if you could introduce so
NV instrument for the purpose Of meas
"a ing the pressure at different points
in the bottom of the jar, IN the sa
manner as we measure the pressure
any the atmosphere with a barometer, ,
lus- would observe the following conditio
lle:e' The pressure would be cohparativ
'aE+ light in the central air column, Fl
or because the air is so much less de
be than the water, and, second, beca
tier of the rapid upward movement.
who fact, if we could take the measurem
his independent Of the weight Of the
- :, side atmosphere, the pressure in
= ~ No, case would be upward. Also, INN
, To to ately around the air column where
, on movement of the water is upward,
and pressure would be less than it VIZ
an away from this column where
Tor movement is downward. This illus
ern- ton uses extreme conditions, for in
, na1I atmospheric relations we never /
such difference in densities as exists