Now, the curious fact is, when the number and violence of magnetic
storms are recorded and compared, it is found that they correspond
to the spots on the sun, and go through the same period of eleven
years. The conclusion seems almost inevitable: magnetic storms are
due to some emanation sent out by the sun, which arises from the
same cause that produces the spots. This emanation does not go on
incessantly, but only in an occasional way, as storms follow each
other on the earth. What is it? Every attempt to detect it has
been in vain. Professor Hale, at the Yerkes Observatory, has had
in operation from time to time, for several years, his ingenious
spectroheliograph, which photographs the sun by a single ray of
the spectrum. This instrument shows that violent actions are going
on in the sun, which ordinary observation would never lead us to
suspect. But it has failed to show with certainty any peculiar
emanation at the time of a magnetic storm or anything connected
with such a storm.
A mystery which seems yet more impenetrable is associated with the
so-called new stars which blaze forth from time to time. These
offer to our sight the most astounding phenomena ever presented to
the physical philosopher.
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