t was found, however, that the agreement
in the lines of different spectra was not perfect. Lines would be
found in the spectrum derived from one source that were not present in
a spectrum derived from another source. Materials were therefore
suggested as present in one body that were not present in another.
Still further inquiry confirmed the belief that while there is a
general uniformity in the materials of our solar system, the identity
is not complete in all. An element is found in one part that may not
be found in another. Hydrogen shows its line in the spectrum derived
from every heavenly body that has been investigated; but not so
aluminium or cobalt. Sodium, that is, the salt-producing base, is
discovered everywhere, but not nickel or arsenium. The result, in a
word, shows a certain variability in the distribution of solar and
planetary matter, but a general identity of most.

The question next presented itself as to the character of the luminous
bodies _beyond_ the solar system. Of what kind of matter are the
comets? Of what kind are the fixed stars? Of what kind are the nebulae?
Could the spectroscope be used in determining also the character of
the materials in those orbs that we see shining in the depths of
space? The instrument was turned in answer to these questions to the
sidereal heavens. No other branch of science has been prosecuted in
the after half of this century with more zeal and success than has the
spectroscopic analysis of the fixed stars. These are known by the
telescope to have the character of suns. The most general fact of the
visible heavens is the plentiful distribution of suns. They sparkle
everywhere as the so-called fixed stars. To them the telescope has
been virtually turned in vain. We say in vain because no single fixed
star has, we believe, ever been made by aid of the telescope to show a
disc.

On turning the telescope to a fixed star, its brightness, its
brilliancy, increases according to the power of the instrument. Coming
into the field of one of these great suns of space, the telescope
shows a miraculous dawn spreading and blazing into a glorious sunrise,
and a sun itself flaming like infinite majesty on the sight; but there
is no disc--nothing but a blaze of glory. Thus in a sense the
telescope has worked in vain on the visible heavens. But not so the
spectroscope. The latter has done its glorious work. Turning to a
given fixed star, it shows that the tremendous combustion