ost remarkable discoveries
ever made is that which has taught us that the elementary bodies of
which the sun and the stars are constructed are essentially the same
as those of which the earth has been built. This discovery was indeed
as unexpected as it is interesting. Could we ever have anticipated
that a body ninety-three millions of miles away, as the sun is, or a
hundred million of millions of miles distant, as a star may be, should
actually prove to have been formed from the same materials as those
which compose this earth of ours and all which it contains, whether
animate or inanimate? Yet such is indeed the fact. We are thus, in
a measure, prepared to find that the material which forms the great
solar clouds may turn out to be a substance not quite unknown to the
terrestrial chemist. Nay, further, its very abundance in the sun might
seem to suggest that this particular material might perhaps prove to
be one which was very abundant on the earth.

[Illustration: THE SUN'S CORONA.

From a photograph taken by Professor Schaeberle, at Mina Bronces,
Chili, in April, 1893, and kindly loaned by Professor E.S. Holden,
director of the Lick Observatory.]

I had occasion to make use of the word carbon in a lecture which
I gave a short time ago, and I thought when I did so that I was of
course merely using a term with whose meaning all my audience must be
well acquainted. But I found out afterwards that in this matter I had
been mistaken. I was told that my introduction of the word carbon had
quite puzzled some of those who were listening to me. I learned that a
few of those who were unfamiliar with this word went to a gentleman
of their acquaintance who they thought would be likely to know, and
begged from him an explanation of this mysterious term; whereupon he
told them that he was not quite sure himself, but believed that carbon
was something which was made out of nitro-glycerine! Even at the risk
of telling what every schoolboy ought to know, I will say that
carbon is one of the commonest as well as one of the most remarkable
substances in nature. A lump of coke only differs from a piece
of carbon by the ash which the coke leaves behind when burned. As
charcoal is almost entirely carbon, so wood is largely composed of
this same element. Carbon is indeed present everywhere. In various
forms carbon is in the earth beneath our feet, and in the air which we
breath. This substance courses with the blood through our veins;