Evening star., 1939-04-29
Of Stors, Men
And Atoms
Notebook Of Science Progress
In Field, Laboratory
And Study
By Thomas r. Henry.

Some July day washington may
swelter with temperature OF ia.
1t can happen approximately once in a
thousand years. G. H. Slocum OF the
United States Weather Bureau staff told
the American Meteorological Society
here, today.
The city may also hit a low Of 18 below
about January 25, some year. This Is
much more likely and can be expected
once in about 200 years.
The nearest these marks have been
approached during the so years for which
daily records are, available, Mr.. Slocum
said. is 100 above and is below.
He based his calculations on the dates
of the highest and lowest recorded tenn
ample, there has been one March % with
a temperature of 80. On that date the
sun still has nearly three months to go
before attaining its highest elevation OF
the year. The earth and atmosphere
have barely started storing up more heat
during the day than they lose at night,
and the excess will be continuous
through the spring and summer. On the
other hand the sun is getting farther
away from the earth in space, a factor
responsible for about six degrees differ
ence in temperature during the year.
Mr. Slocum balances all these factors
and, assuming SO to be the highest pos
sible temperature for March, finds that
it could be 81 degrees higher some time
between June % and July H. 1t would
not fall on the day of the summer SOL
stice June 81, because Of the lag in the
heat-storing process. BY the same rea-
soning, he finds. the coolest day would
not be expected to fall on the day of the
winter solstice, December 81, but slightly
more than a month later. This Is be-
cause the earth still has an excess Of
temperature stored from the summer.
Early in January it has lost all Of this
and is losing every night about all 1t
gains during the day. 1.
About the end of January, with the
sun getting higher in the sky, it starts
storing heat again. but very slowly at
first.
The maximum hot or cold temperature.
MI. Slocum points out, would depend on
an ideal combination Of all the factors
at one time. His statistics show that
this is more likely to occur for cold than
for heat. Only once in so years'has there
been temperature of los and very rarely
has the mercury gone much above 1902
Cold of 10 or IL below can be expected
every few years and the weather man
would have less of a struggle pushing it
down to the minimum l8.
The records show, Mr. Slocum told the
meteorologists that for the past go years
the January thaw. coming probably on
January 81 or %, has been a reality
throughout the East, although there is
no logical explanation for it. The tenn
perature averages, he found, three to
four degrees warmer on those two days
year after year. This does not apply
everywhere every year, so in order to
make up the averages some places must
experience really abnormal heat.
The strangest part of it, he says, Is
that the thaW comes two or three days
before the theoretical coolest point of the
year.
Il can't believe it is really true" he
said. IF We had the records for 1000
years 1 am almost sure it would disap-
pear"
The last day on which killing frost
Is possible in this area, he said, is May %.
The mercury theoretically may 60 as
low as zero in April
Every month in the year except Janu-
ary, he found, may have few days too
hot for any artificial heat. This has
been the case twice in 60 years in Feb
ruary. On the other hand every month
In the year may have days cold enough
for fire.
Invisible electric clouds in the earths
high atmosphere, apparently rushing
past with speeds of close to 400 miles an
hour, were described to the American
Physical Society here today by Drs. j. A.
Pierce and H. r. Mimno of Harvard
University.
These clouds may be very small or
hundreds Of square miles in area. Usu-
ally they are a few miles thick. They
are clouds of ions, atoms of the atmo-
spheric gasses which have been stripped
OF one of their outer electrons by the
actions of bullets OF ultraviolet light
from the sun.
Specifically, the Harvard scientists
said, they seem like broken off frag-
ments of the E layer of the ionosphere,
the electrified strata 80 to 100 miles
above the earth's surface which stops ra-
dio waves from continuing in straight
line into space and makes them follow
the curve of the earth. This makes long
distance transmission possible. The
clouds" when they appear, introduce
unexpected complications into radio
transmission.
Actually, DR.. Pierce reported, they
only seem to be flying clouds. What
happens, he believes, is that a beam of
ultraviolet light from the sun sweeps
across the atmosphere, creating ions as
1t moves. These rapidly recombine with
their lost electrons as soon as the beam
has passed. The effect, however, is that
OF a single great chunk of the high
atmosphere in rapid motion. Since the
ionosphere is far above the level of the
winds there would be nothing to account
for such motion of an air mass.