. Trans._, vol. ci., p. 306.]

[Footnote 1363: _Conn. des Temps_, 1816, p. 213.]

[Footnote 1364: _OEuvres_, t. vi., p. 581.]

[Footnote 1365: _Mem. dell' Istit. Lombardo_, t. xii., p. 164;
_Rendiconti_, t. vii., p. 77, 1874.]

[Footnote 1366: W. Foerster, _Pop. Mitth._, 1879, p. 7; Fabry, _Etude sur
la Probabilite des Cometes Hyperboliques_, Marseille, 1893, p. 158.]

[Footnote 1367: _Mem. R. A. Soc._, vol. xxix., p. 335.]

[Footnote 1368: _Month. Not._, vol. xxiii., p. 203.]

CHAPTER XII

_STARS AND NEBULAE_

That a science of stellar chemistry should not only have become
possible, but should already have made material advances, is assuredly
one of the most amazing features in the swift progress of knowledge our
age has witnessed. Custom can never blunt the wonder with which we must
regard the achievement of compelling rays emanating from a source devoid
of sensible magnitude through immeasurable distance, to reveal, by its
distinctive qualities, the composition of that source. The discovery of
revolving double stars assured us that the great governing force of the
planetary movements, and of our own material existence, sways equally
the courses of the farthest suns in space; the application of prismatic
analysis certified to the presence in the stars of the familiar
materials, no less of the earth we tread, than of the human bodies built
up out of its dust and circumambient vapours.

We have seen that, as early as 1823, Fraunhofer ascertained the generic
participation of stellar light in the peculiarity by which sunlight,
spread out by transmission through a prism, shows numerous transverse
rulings of interrupting darkness. No sooner had Kirchhoff supplied the
key to the hidden meaning of those ciphered characters than it was
eagerly turned to the interpretation of the dim scrolls unfolded in the
spectra of the stars. Donati made at Florence in 1860 the first efforts
in this direction; but with little result, owing to the imperfections of
the instrumental means at his command. His comparative failure, however,
was a prelude to others' success. Almost simultaneously, in 1862, the
novel line of investigation was entered upon by Huggins near London, by
Father Secchi at Rome, and by Lewis M. Rutherfurd in New York.
Fraunhofer's device of using a cylindrical lens for the purpose of
giving a second dimension to stellar spectra was adopted by all,