Volcanoes: What They are and What They Teach

by John W. Judd

In [fig. 89] a group of sun-spots is represented and, in their circular outlines and tendency to a linear arrangement, they can scarcely fail to remind anyone familiar with volcanic phenomena of terrestrial craters, though their dimensions are so much greater.

In [fig. 90] the sun-spot represented shows the presence of large floating masses of incandescent materials rushing upwards and downwards within the yawning gulf.

PHENOMENA OF SUN-SPOTS.

Fig. 90.—A Sun-spot, showing the great masses of incandescent vapour rising or falling within it. (After Secchi.)

Fig. 91.—The edge of a Sun-spot, showing a portion of the prominent masses of incandescent gas (A), which detached itself at E and floated into the midst of the cavity.

From [fig. 91], taken from a drawing by Mr. Norman Lockyer, we may understand the movements of these great protuberances of incandescent gas which are seen on the sides of the sun-spots.

The so-called solar prominences present even more striking resemblances to the volcanic outbursts of our globe.

Two drawings made by Mr. Norman Lockyer will serve to give some idea of the vast dimensions of these solar prominences, and of the rapid changes which take place in their form.