n's heat being absorbed by the air. Yet the
deeper man digs beyond the hundred feet, the warmer he finds the earth,
and that at a somewhat determinable rate of increase. Supposing that
rate of increment to go on toward the centre, it is computable that the
solid underwork of the world, say granite by way of conjecture, must be
in a state of fusion at no vast depth from the ground on which we tread.
Let the scientific imagination descend a little lower, and it will find
the melted granite in the form of a fiery vapor or gas--the dry steam of
a red-hot liquid, in which the rock-built foundations of "the
everlasting hills" melt like icebergs. But this is conjectural and
probable, not observable and proved.

Far away from this spinning and perilous globe of ours, at the distance
of some 95,000,000 miles, stands the sun. A ray of light, starting from
his surface at any given moment, takes eight minutes to reach us,
although light runs at the speed of 195,000 miles in a second. The sun
is 1,380,000 times as large as the earth, and 355,000 times as heavy;
but the stuff of which he is made is just about a fourth part as dense
as the average matter of this world. The sun is of as light a substance,
taking his whole body, as coal; whereas the earth is twice as heavy as
brimstone, striking the mean between the air, the ocean, the dry land,
and the internal vapor. The sun has an atmosphere like the earth, or
rather he has two. One of them, close upon his solid surface, seems to
resemble our own; it bears cloudy bodies in its upper levels. The other
is a sort of fiery gas, surrounding the former, kindled and sustained in
the calorific and luminous state, no man knows or can conjecture how.
Storms in the lower atmosphere are constantly blowing this
phosphorescent airy envelope aside, so as to afford us glimpses down
into the (comparatively) dark and black recesses beneath. These are the
spots on the sun. Galileo inferred the rotation of the sun on his axis
from the motions of those spots. The explanation of those spots,
afforded by the discoveries of Wilson and Herschel, diminishes the value
of the inference; but no Copernican can doubt that the sun is forever
turning, and that with unimaginable swiftness and impetuosity.

At the distance, then, of more than ninety-five millions of miles, this
dim spot which men call earth, this great globe and all its dwellers,
this ever-spinning planet, revolves around the sun once every year, that