the particles composing the coronal matter, are separated from each
other by a distance of perhaps between two and three yards! The density
of the corona is found not to increase inwards towards the sun. This is
what has already been noted with regard to the layers lying beneath it.
Powerful forces, acting in opposition to gravity, must hold sway here
also.

[Illustration: (A.) THE TOTAL ECLIPSE OF THE SUN OF DECEMBER 22ND, 1870

Drawn by Mr. W.H. Wesley from a photograph taken at Syracuse by Mr.
Brothers. This is the type of corona seen at the time of _greatest_
sunspot activity. The coronas of 1882 (Plate I., p. 96) and of 1905
(Frontispiece) are of the same type.

(B.) THE TOTAL ECLIPSE OF THE SUN OF MAY 28TH, 1900

Drawn by Mr. W.H. Wesley from photographs taken by Mr. E.W. Maunder.
This is the type of corona seen when the sunspots are _least_ active.
Compare the "Ring with Wings," Fig. 7, p. 87.

PLATE VII. FORMS OF THE SOLAR CORONA AT THE EPOCHS OF SUNSPOT MAXIMUM
AND SUNSPOT MINIMUM, RESPECTIVELY

(Page 141)]

The 11-1/4 year period, during which the sun spots vary in number and
size, appears to govern the activities of the sun much in the same way
that our year does the changing seasonal conditions of our earth. Not
only, as we have seen, does the corona vary its shape in accordance with
the said period, but the activity of the prominences, and of the faculae,
follow suit. Further, this constant round of ebb and flow is not
confined to the sun itself, but, strangely enough, affects the earth
also. The displays of the aurora borealis, which we experience here,
coincide closely with it, as does also the varying state of the earth's
magnetism. The connection may be still better appreciated when a great
spot, or group of spots, has made its appearance upon the sun. It has,
for example, often been noted that when the solar rotation carries a
spot, or group of spots, across the middle of the visible surface of the
sun, our magnetic and electrical arrangements are disturbed for the time
being. The magnetic needles in our observatories are, for instance, seen
to oscillate violently, telegraphic communication is for a while upset,
and magnificent displays of the aurora borealis illumine our night
skies. Mr. E.W. Maunder, of Greenwich Observatory, who has made a very
careful investigation of this subject, suspects that, when elongated
coronal streamers are whirled round in our direction by the solar
rotation, powe