[Illustration: FIG. 7.--THE VISIBLE SURFACE OF THE SUN
A photograph taken at the Mount Wilson Observatory of the Carnegie
Institution at Washington.]
[Illustration: FIG. 8.--THE SUN
Photographed in the light of glowing hydrogen, at the Mount Wilson
Observatory of the Carnegie Institution of Washington: vortex phenomena
near the spots are especially prominent.]
The fourth and uppermost layer or region is that of the corona, of
immense extent and fading away into the surrounding sky--this we have
already referred to. The diagram (Fig. 5) shows the dispositions of
these various layers of the sun. It is through these several transparent
layers that we see the white light body of the sun.
§ 2