Evening star., 1935-10-15

The heat of the sun, tor some un-
known reason, pulsates.
When all possible allowances have
been made for season. distance from the
earth and atmospheric conditions there
are differences in the solar output OF
radiation which can be explained only
by the assumption that the great disk OF
fire is a variable star. like thousands OF
others in the heavens.
This thesis seems to have been estab-
lished definitely through the observa-
tions of Smithsonian Institution astro-
physicists stationed on Mount st.
Katharine on the Sinai Peninsula
through which Moses led the 1sraelites
to the Promised Land. These observa-
tions show essentially the same day-by-
day variations in the solar heat as are
shown by those taken from the summit
of Mount Montezuma in Chile. on the
other side of the world. Long noted at
the Montezuma station, it was dih1cult
to state positively that the variations
were actual until they could be checked
from an equally favorable observation
point not subjected to the same ter
restrial conditions.
The solar radiation is difficult to
measure and there is considerable oppor-
tunity for error. What must be meas
ured is not the actual solar heating
effect at the surface of the earth but
the effect on a hypothetical black cube
of a cubic centimeter placed at the
limit of the earth's atmosphere. Since
it is impossible to get outside the atmos-
phere to measure such an effect 1t was
necessary to arrive at its value by
various complicated corrections for the
absorption by the layers Of air through
which the solar rays must pass to reach
the surface. Many factors had to be
taken into consideration and every
necessary correction involved another
possibility of error.
Many thousands OF measurements
with increasingly delicate and accurate
instruments showed that on the average,
the solar radiation would raise the heat
of a theoretical black cubic centimeter
1910 calories per minute, but the day
by-day values showed that the actual
effect fluctuated from this average by
amounts which were somewhat above
the expectation from experimental error.
This fact, nevertheless, was difficult Of
rigid proof, although the probabilities
were highly in its favor. The Table
Mountain measurements, although
highly instructive, were somewhat in.
validated at times by some obscure in
visible changes in atmospheric condi-
TONS which long defied exact analysis.
For presentation of the thesis to the
scientific world it was necessary to rely
largely on the Montezuma measure
ments, and it hardy could be stated posi-
lively that the fluctuations observed
might not be, in some part, caused by
unappreciated terrestrial factors Pc
culiar to the locality.
All this has been changed by the
measurements taken on the Sinai Pen
insuia. It was Winter at one station
while Il was Summer at the other.
simultaneously with increased heat,
haziness and humidity at one there
might be increased cold, clearness and
dryness at the other. The altitude OF
the sun differed at the two stations.
Thus the disparity of conditions favored
wide divergence, II caused by terrestrial
sources of error.
Yet despite all this, the two stations
show almost exactly the same solar
radiation fluctuations on the same days.
the average daily differences being only
four-tenths of / per cent Of the solar
constant. The Mount st. Katharine
measurements for II months have just
been analyzed by Dr. Charles 6. Abbot,
secretary of the Smithsonian Institution.
The correspondence with the Montezuma
figures is remarkable.
These two stations" says DR.. Abbot.
obviously support eaca other In diss