it is
by carbon that the heat of the body is sustained; and the same element
is intimately associated with life in every phase. Nor is the presence
of carbon merely confined to this earth. We know it abounds on other
bodies in space. It has been shown to be eminently characteristic of
the composition of comets. Carbon is not only intimately associated
with articles of daily utility, and of plenteous abundance, but with
the most exquisite gems of "purest ray serene." More precious than
gold, more precious than rubies, the diamond itself is no more than
the same element in crystalline form. But the greatest of all the
functions of carbon in the universe has yet to be mentioned. This same
wonderful element has been shown to be in all probability the material
which constitutes those glowing solar clouds to whose kindly radiation
our very life owes its origin.

[Illustration: At 10.34 A.M. The height of the eruption at this stage
was 135,200 miles.]

[Illustration: At 10.40 A.M. Height, 161,500 miles.]

[Illustration: At 10.58 A.M. Height, 280,800 miles.

THREE VIEWS OF AN ERUPTIVE PROMINENCE OF THE SUN.

From photographs taken at Kenwood Observatory, Chicago, March 25,
1895, and kindly loaned by Professor George E. Hale, of the Chicago
University.]

In the ordinary incandescent electric lamp, the brilliant light is
produced by a glowing filament of carbon. The powerful current of
electricity experiences so much resistance as it flows through this
badly conducting substance, that it raises the temperature of the
carbon wire so as to make it dazzlingly white-hot. Indeed the carbon
is thus elevated to a temperature far in excess of that which could
be obtained in any other way. The reason why carbon is employed in
the electric lamp, in preference to any other substance, may be easily
understood. Suppose we tried to employ an iron wire as the glowing
filament within the well-known glass globe. Then when the current was
turned on that iron would of course become red-hot and white-hot;
but ere a sufficient temperature had been attained to produce the
requisite illumination, the iron wire would have been fused into drops
of liquid, the current would have been broken, and the lamp would have
been destroyed. Nor would the attempt to make an incandescent lamp
have proved much more successful had the filament been made of
any other metal. The least fusible of metals is the costly element
platinum, but even a wire of platinum,