Deseret evening news. [volume] (Great Salt Lake City [Utah]) 1867-1920, 1906-07-09


tor and his aids, obtained the following
interesting resume OF the subject The
officials of the bureau were much inter-
ested Ia the articles that have appeared
In the News ON the subject, and TX
tended an invitation to the nature
study class at the university TO call
and Inspect the operations Of the de-
partment.
OUR LARGER STORMS.
"our larger storms. Ike an other
storms" said Nj Hyatt, are preced-
ed by a falling barometer. The BAR
ometer IN Salt Lake City stands nor
mally at 1852 inches, indicating an air
pressure Of about y pounds AZ sea
level the barometer Is normal AZ ~
inches. indicating am air pressure OF 10
pounds to the square inch. Before a
storms IN Utah, The barometer may Tan
during several days from as high as
26.gS right after storm Jan. H. lsSS)
down to as low as PASS NOV. q, 1851
"a difference equal 10 a change OF
400 feet iu altitude but the usual range
here Is between % and % inches. For
several days before our storms, when
the storm is slowly approaching, the
wind blows from the southeast, which
We commonly cali a south wind This
is because the storm approaches from
the northeast and the pressure Is low
for considerable distance northeast
because the storm is thereabouts;
while the nearest high pressure area IN
such cases win be on the southeast IL
the wind is from the southeast for sew
eral days. 10 precedes a general storm
from tn northwest. When the storm
arrives. the wind win shift, blowing
first in one direction. and, after the
storm center has passed, In the con-
trary direction. as already explained.
The center Of the storm viii pass near
or TO the south or east Of the observer
within Il GO "A hours after the wind
has set In from the southwest, and the
winds meantime will shift 20 the north
west The rapidity Of the storms ap-
proach will be- indicated by the rate
and amount OF the fall IN the barom-
tier.
THE STORM TRACK
The storms of the United States fol-
low series Of tracks. not capricious
but related 10 each other by very we'll
defined laws The positions Of these
racks have been determined by studies
made On the forecast division Of the
weather bureau The chart shows the
general result Of a study OF the tracks
II storms in this country There are
Two sets Of tracks. one over the lake
region aud the 81. Lawrence valley. the
ithcr over The middle Rocky mountain
districts ana the gulf states Each NJ
hese Is d0uhie.With one for the highs
md one TO- The lows II Is difficult
o tel in advance which Of these paths /
he storm win take and al what rate 4
Z will travel The transverse broken |
ines show the average daily movement, /
nd that II lakes about four days for
torn 90 cross the continent. Low In
icates low pressure. and the ceuters u /
reas Of high hsrometric pressure
heavy air. arc indicated by the word
high" These alternating highs and /
lows" uass eastward over the United
tatcs M the rate Of COO 10 700 miles a
ay. They are similar to a series ~
tmosphcric waves. the CrcSts of which
rc high. the troughs low
RAIN IN STORMS.
Tho eastward advance Of "lows' Is
lmost invariably attended by rain ar
now. while "hlgh" brings clear
Gather. Whether "a rain Is imminent I
ith or without a general storm, may
ways be aScertained O by noting I
be- temperature OF the thermometer !
nd 90 by wrapping It's mercury bulb
a piece 81 cloth. dipping IL into wa
n. then whirliug % around for a |
inutc and finally reading this .
Ket' thermometer. Il the two read I
gs are near together. the air is nearly
.turated and should the air grow cool
d. rain is slmost sure 10 fall But II
c air Is growing warmer there VIII be
, rain, since the capacity 81 the cir
hold moisture Increases with a rise
& temperature. When the readings Of
e wet and the dry thermometer coln-
Dc. the air Is saturated. since Il Is the
te OF evaporation that lowers the
aiding ~ the wet bulb. In the expert
ent performed hy Mr.. Hyatt for the
,ews' representative on Saturday the
y thermometer stood az ~. and the
II one AT ga difference Of rs le-
ees. showing that the atmosphere Z 2
ntaincd only SO per cent toward COM .
tie saturation. or the point az which =
aciptatIon win occur
THUNDER SHOWERS. :
!, SUMMER thunderstorm may be 10. G
/. a LAYER OF cirTO-stratus clouds U.s. "
lly appears Zoo the west. followed by %
-k idIu clouds The air is hot ana
Nd winds come from ,hc south c0oI. p
lust before ne Storm arrives. aF r
clouds oyerspread ine sun. Distant @
udcr is heard. The Clouds change
2 grow dark 4 hitf wind slual '
s in. cooler than the south wind and b
sing ta, dust III, barometer which I
5 been falling an along. now rises
little. hut sinks as the Wind dies 4
80. As the storm breaks the bal1m- n
o. r.rcs again The rsln begins in n
Pc. peluns dlopa, The lightning n
Ges. and the thunder rolls The VI
.m moves rapidly. and iu half au n
DO tlC sky clears IN
MEANING OF THESE FACTS. N
ne air is rarely stlL Even when y
think that uni Cd ielf Is surlng'
that the winds aTc "a; rest. there Z
Usually some motion Of the afmos Y
re- MhF is tle ail s0 restless. We "
o. seen that this is due io tne uu-
U heating Of the carth's surface by 4
sun and che ever vagfHg auoal n
water and NaIor poured luto sr I'll
Iltaen from ,hs air This changes IN
snDtt az ihe density o. pfessura of 4,
ulUDfphTe. ana abe movements 90 M
air arise out 1f diNerncis oi pes- IN
/. il accordance Win ODE following In
To- always flows .n sp.raily nom "
.s az h.sh pressure 20 areas ~ .os !
furr LuN pressure indicates u
eucy and high pressure Cd surplus y
.r. =