Evening star., 1937-07-13

The great Western drouths follow the
sunspots. but in a rather complex way.
The rainfall record for the past half
century shows that the extremely dry
periods have accompa MED sharp changes
in the numbers Of these stormy areas on
the face of the sun. The change may
be in either direction.
Evidence to this effect was presented
In report prepared at the desert
laboratory OF the Carnegie Institution Of
Washington at the annual meeting Of
the American Association for the Ad-
vancement Of Science In Denver.
In the past there has been abundant
evidence that drouths and periods Of
normal rainfall succeed each other in
the range country and that there Is some
sort Of cyclic phenomenon involved. The
difnculty has been to find some high
correlation which holds up over 4 long
period.
Sunspots long have been suspected.
The difnculty has been that the dry
periods seemed to follow the sunspot
cycle rather indifferently. The cycle
from sunspot minimum to maximum
and back to minimum again takes ap-
proximately eleven years and six months.
Drouths have come roughly At 23-year
intervals, or intervals OF double the SUM-
spot cycle. They have come, however
when there were great numbers OF dis
turbed areas on the sun and when there
were very few.
The report also pointed out that there
have been at least four cycles OF settle
ment in the drouth country. and that
these have been closely correlated with
he 4f {1ah eN}~
f1rst came Immediately after the Civil
War. when the men just released from
military service went West by the thou
sands. They ran into the great drouth
OF the early seventies and the worst
plague Of grasshoppers ever known in
America. Then came the dry period OF
1889, followed closely by that Of 1893,
when half million disillusioned settlers
returned to their homes In the East.
Their places, however, were quickly
taken by new generation. These
settlers met with exceptionally rainy
weather and confidently predicted that
the climate had permanently changed.
The next major drouth came during the
war when prices were 50 high that 1t
passed without much notice. Until the
great drouth OF 1890. coming coincidently
WIFI CIlc CCOIlOkxllC CIASIl, CIlC lIcVlIAUlllty
OF the cycle hardly was realized.
Says the report:
I'm the hope Of discovering . connec-
ton between drouth and sunspot ex-
tremes." says the report. "the rainfall
records of all stations In the Middle and
Far West were compiled. The nrst out
come of this study was the discovery
that the three greatest drouths fell at
high sunspot maxima-in 1S70-72. 1893
IS and lel7-19, when. the number Of
sunspots for the year Of maximum
averaged l3o, IS and 104, respectively.
The alternate maxima Of 1883 and 1905
were marked by . relatively low num-
Der OF spots. namely, 63, and rains were
generally good to excellent in and about
these years. At frst glance 1t would
appear inconsistent on the basis Of
energy relations to find drouth at cer-
tain maxima and high rainfall at others,
but 1t is plausible to assume that the
large differences In actual solar output
would be reflected In the precipitation.
Tentative forecasts Of 4 maximum Of
about 100 spots in 1917 attended by seri-
Gus drouth and Of approximately IS