SOLAR VARIATION AND WEATHER—ABBOT 137 
partures at Washington for the 12 months, as associated both with 
solar-constant sequences and with flocculus character-figure sequences. 
It is at once apparent that similar curves of temperature resulted, 
but that the curves based on flocculus character figures show 2 days’ 
lag in phase compared to the curves based on solar constants. The two 
kinds of solar change, in other words, are not exactly simultaneous. 
The reader will see in the diagram that for comparison purposes the 
flocculus temperature curves are all moved to the right 2 days with 
respect to the solar-constant-temperature curves. This phase dif- 
ference allowed for, the correlation coefficient between solar-constant 
and flocculus temperature curves for Washington is r=59.7+1.9 per- 
cent. It will be noted that the two systems of dates used for the two 
determinations have almost nothing in common. They are spread 
over two different series of years, one interval 1910 to 1937, the other 
1924 to 1939. Owing to differences in days lost for cloudiness in Spain 
and northern Chile, only a few of the dates in the two intervals are 
adjacent. In short, in method, in the years observed, and in detail, 
the two determinations have only this in common: both purport to 
show the influence of changes of solar activity on Washington tem- 
perature. One of the methods uses photographic phenomena univer- 
sally admitted to be solar. Since the results of the two methods are 
well-nigh identical, how can critics longer reasonably deny that in the 
basis of the other method (the solar-constant variation) is also 
a truly veridical solar phenomenon ? 
I therefore claim for the Smithsonian Institution the discovery and 
measurement of variations of the solar constant of radiation, and the 
proof that these solar variations are major factors in the control of 
terrestrial temperatures. 
SOLAR SEQUENCES AND BAROMETRIC PRESSURE 
We have investigated also the dependence of barometric pressure 
on the solar variations tabulated in table2. I will not enter extensively 
into this branch of the subject, nor show further examples of the tem- 
perature effects, because I have much else to present in this lecture. I 
will only draw attention to the march of barometric pressure at Denver 
and Ebro (figs. 10, 11) for the 12 months, as associated with rising and 
falling sequences of solar-constant changes. It will be seen that the 
curves, while not so consistent as the temperature curves, already 
shown, still generally display that right-and-left symmetry which has 
been referred to in temperature. 
POSSIBILITIES OF DETAILED LONG-RANGE FORECASTING 
I now turn to the question whether these solar variations, since indi- 
vidually they apparently produce major changes of weather for inter- 
