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tent man would find it possible to point out the true cause 
of these regularities. 
Meanwhile conversations with meteorologists and bota- 
nists have left me little hope that it will be so. What 
J heard and what I read has long brought me to think, 
that in the present state of science any investigation on 
long period regularity in the weather must be a purely 
empirical one. The case stands much as with another 
question in the olden time of the Chaldaeans. At that 
time the eclipses were the all-important astronomical 
phenomena and, wanting to be able to predict them, they 
sought whether there were any regularity in their occur- 
rence. 
They found that there was: that after the lapse of 6585 
days and 8 hours they recurred pretty nearly in the same 
order and appearance. This is the famous period called 
the Saros. They must have found this simply by making 
long long lists of eclipses, continued for many many years, 
in very different places of the earth. From such lists they 
might find out what they sought for, without their knowing 
the true theory of the motions of Sun and Moon, that is 
without their being really scientific astronomers. Their 
hope was not in vain. Ît must have been by means of 
this Saros that Thales was enabled, 600 years before 
Christ, to predict his famous eclipse. 
Now, as it was with the eclipses, it might be with the 
weather. Though the empirical finding out of a regularity 
may hardly be claimed as a scientific achievement, it may 
nevertheless become in future of the greatest utility in 
weather forecast a long time in advance. 
But there is more, which makes that, at the present 
time, the problem may be taken up by other men nearly 
as well as by meteorologists. Take the rain. In order 
to find out whether there be any regularity in the 
recurrence of wet and dry years, if we will have any 
