down here to make us comfortable. When you
climb to the top of a high mountain you pass through a large part of
the air. This is the reason why you feel warmer on the surface of the
earth than you do on the top of a high mountain. If, however, it were
possible to go very much closer to the sun; if, for example, the earth
were to approach within half its present distance, it is certain that
the heat would be so intense that all life would be immediately
scorched away.

It will be remembered that when Nebuchadnezzar condemned the unhappy
Shadrach, Meshach, and Abednego to be cast into the burning fiery
furnace, he commanded in his fury that the furnace should be heated
seven times hotter than it was wont to be heated. Let us think of the
hottest furnace which the minions of Nebuchadnezzar could ever have
kindled with all the resources of Babylon; let us think indeed of one
of the most perfect of modern furnaces, in which even a substance so
refractory as steel, having first attained a dazzling brilliance, can
be melted so as to run like water; let us imagine the heat-dispensing
power of that glittering liquid to be multiplied sevenfold; let us go
beyond Nebuchadnezzar's frenzied command, and imagine the efficiency
of our furnace to be ten or twelve times as great as that which he
commanded--we shall then obtain a notion of a heat-giving power
corresponding to that which would be found in the wonderful celestial
furnace, the great sun in heaven.

[Illustration: SIR ROBERT BALL. From a photograph by Russel & Sons,
London.]

Ponder also upon the stupendous size of that orb, which glows at every
point of its surface with the astonishing fervor I have indicated. The
earth on which we stand is no doubt a mighty globe, measuring as it
does eight thousand miles in diameter; yet what are its dimensions in
comparison with those of the sun? If the earth be represented by a
grain of mustard seed, then on the same scale the sun should be
represented by a cocoanut. Perhaps, however, a more impressive
conception of the dimensions of the great orb of day may be obtained
in this way. Think of the moon, the queen of the night, which circles
monthly around our heavens, pursuing, as she does, a majestic track,
at a distance of two hundred and forty thousand miles from the earth.
Yet the sun is so vast that if it were a hollow ball, and if the earth
were placed at the centre of that ball, the moon could revolve in the
orbit which it now f