Richmond times-dispatch. [volume] (Richmond, Va.) 1914-current, 1920-04-25
THUNDERsTORMs SEEM
TO PREVAIL IN HOT CITIES
Prevalence OF Electrical Disturb
anccS i'm Tropics Indicates de-
pcndcncc OH Evaporation.
ny GARRETT 4. SERVISS.

Our class in science would like -
know shy it does not 'hInier and
kindiy tell uS?-F. NJ"
/, does thunder and lighting IN
winter sometimes. though tar less
ottcp shan in summer. especially n
but there ar. places where ;hundcr.
storms usually occur in winter AMI
not in summer; For instance, IN lee
land winter ,hunderstoTms are ne
Quen; and summer ones rare. III
Norway there are AS many winter as
summer ;hunGcrstormJ. and the Win
Ter ones are ;hc more violent
Generally ;nc frequency OF shundtr-
farther north YOU E". This, ioErih"r
Win ihc great Noisncc OF The ihun-
derStoC:nS tina; occur within the
tropics. indicates ;hnt they are som:-
how associa,,a WITH variations in the
amount OF heat derived from ;he Sun
The association - aa Indirect one,
being manifested through the In
creased evaporation OF water that oc-
ours ia heated weather. and rhr for
nation OF ascending currents ri
moisture Laden air.
In ;hc United states generally. al
though there are wide variations II
;hr average number occurring IN dit-
iercn; parts OF the country. thunder
storms are mos; frequent III July.
little less frequent in June, still less
in August, while IN May ;hc Num-
In April and september they are i've
or six times .-ss numerous than In
July. while they are quite rare III
March and October.
There are curious differences In
the liability OF different sections at
the United StatrS tamd ihc same Is
true Ot some foreign couutr!cSp 10
the occurrence ot ihundrvstorms. The
WcntRer Bureau has reported three
maximum rrgi"uS Of thunderstorm
Frequency. one IL che Southeast. CEN
ter:nr around Florida. another III tn.
.nidG,c OF the Miss .sSippi Valley, anal
a third in the Missouri Valley The
Rocky Mountains have many thun-
dersturms. while the Pacific Coast
has none.
Among foreign countries France Is
remarkable for lis frequent and ex-
tcusivc thundcrStormS. sometimes &C
cumHan!cd 10y very destructive storms
OF hail III France thcr" are many
more wiatc. thundcTstorms ;han in
The United States. some statistics
showing tina; the number in the fou:
months .! November. December. Jan
uary and February IL between seven
teen and eighteen t.E,rS as great az In
the United States during the same
months
on The other hand. ;hc summer per
centasc -. ~. storms in France is
smaller than IL th. emitted States. In
other words tines are more distributed
through ;Ir year and icss conccn-
tratcd IN The summer months than
in The case LrIc. This Concurs with
VIVA, has already been said about
the relative incrras" of winter thun-
dcrstOrnrH in higher attitudes. since
France lies !nrth"r north than we
do.
when We c"nsitrr ~. ,nach.ncr!
NJ a ;hundrrs'errl We can begin To
see why IL The summer months OF
temperate attitudes. as we'll aS III the
not zou" ho:'!ercd by the tropics.
,htsc .orm!dahlc :lIrtJnrs are pnrticu-
.aI.y freGu-n, ana violent. hh,n-
der Is lirhtnIng'> voice, and lightning
- an electrical discharge from a cloud
on Witch an enormous clnctrirai
tension has Seen accumulated
THIS accumulation % r.cc;ri.ity il
effected by The :o.,lcsrcnce uf mul-
titudcs az minute a!nirops. or par
,icles % ynpor anrh al which bears
an electro charge dG. probably
TO tn" action ~ evaporation. Tn.
invisible vapor tr"m which ;hes. arr
armed rises rom ;hc warm earth
in RAP! ascending columns. ana ON
reaching the c".1er region oi tn,
atmosphere mile ar So above me
ground. is condensed into drops and
particles. ;hus caus.nE the tops OF
these ascending columns q. moist air
10 appear. on 4 hot summer after
noon. IN the form OF magnificent
domes and :naYscs Ul snow white
compact looking cloud. called 'cumuN,
or sometimes ''thc~-cr- heads"
Within them the minute drops
swiftly coalcncc. thus forming much
Larger drops. Now. as above said.
each or tn" original small drops
bore an electric charge. But when a
large number @: small spheres com
bine into one. the extent OF surface
relative TO the volume Is diminished.
For Instance. suppose that thou
sand little charged globulrs merge
into single large drop. then by geo
hetrical law that crop will have n
sur: ne oniy 100 times Az great al
that OF any one o! the component
Elobr!ee. hut. since an electric
snarge can reside only on the sur
race. All O! the electricity which the