-head' before alluded to had grown and developed
wonderfully into a mass of rolling and ever-changing flame, to speak
according to appearances. First, it was crowded down, as it were,
along the solar surface; later, it arose almost pyramidally 50,000
miles in height; then [Page 88] its summit was drawn down into long
filaments and threads, which were most curiously rolled backward and
forward, like the volutes of an Ionic capital, and finally faded
away, and by half-past two had vanished like the other. The whole
phenomenon suggested most forcibly the idea of an explosion under
the great prominence, acting mainly upward, but also in all
directions outward; and then, after an interval, followed by a
corresponding in-rush."

No language can convey nor mind conceive an idea of the fierce
commotion we here contemplate. If we call these movements hurricanes,
we must remember that what we use as a figure moves but one hundred
miles an hour, while these move one hundred miles a second. Such
storms of fire on earth, "coming down upon us from the north, would,
in thirty seconds after they had crossed the St. Lawrence, be in
the Gulf of Mexico, carrying with them the whole surface of the
continent in a mass not simply of ruins but of glowing vapor, in
which the vapors arising from the dissolution of the materials
composing the cities of Boston, New York, and Chicago would be
mixed in a single indistinguishable cloud." In the presence of
these evident visions of an actual body in furious flame, we need
hesitate no longer in accepting as true the words of St. Peter
of the time "in which the [atmospheric] heavens shall pass away
with a great noise, and the elements shall melt with fervent heat;
the earth also, and the works that are therein, shall be burned
up."

This region of discontinuous flame below the corona is called the
chromosphere. Hydrogen is the principal material of its upper part;
iron, magnesium, and other [Page 89] metals, some of them as yet
unknown on earth, but having a record in the spectrum, in the denser
parts below. If these fierce fires are a part of the Sun, as they
assuredly are, its diameter would be from 1,060,000 to 1,260,000
miles.

Let us approach even nearer. We see a clearly recognized even disk,
of equal dimensions in every direction. This is the photosphere.
We here reach some definitely measurable data for estimating its
visible size. We already know its distance. Its disk subtends an
angle