s obliged me
to make of the anterior conjectures by Fontenelle, by Bradley, by Mayer,
and by Lambert.

By the side of this great discovery we should place another, that seems
likely to expand in future. The results which it allows us to hope for
will be of extreme importance. The discovery here alluded to was
announced to the learned world in 1803; it is that of the reciprocal
dependence of several stars, connected the one with the other, as the
several planets and their satellites of our system are with the sun.

Let us to these immortal labours add the ingenious ideas that we owe to
Herschel on the nebulae, on the constitution of the Milky-way, on the
universe as a whole; ideas which almost by themselves constitute the
actual history of the formation of the worlds, and we cannot but have a
deep reverence for that powerful genius that has scarcely ever erred,
notwithstanding an ardent imagination.

LABOURS RELATIVE TO THE SOLAR SYSTEM.

Herschel occupied himself very much with the sun, but only relative to
its physical constitution. The observations that the illustrious
astronomer made on this subject, the consequences that he deduced from
them, equal the most ingenious discoveries for which the sciences are
indebted to him.

In his important memoir in 1795, the great astronomer declares himself
convinced that the substance by the intermediation of which the sun
shines, cannot be either a liquid, or an elastic fluid. It must be
analogous to our clouds, and float in the transparent atmosphere of that
body. The sun has, according to him, two atmospheres, endowed with
motions quite independent of each other. An elastic fluid of an unknown
nature is being constantly formed on the dark surface of the sun, and
rising up on account of its specific lightness, it forms the _pores_ in
the stratum of reflecting clouds; then, combining with other gases, it
produces the wrinkles in the region of luminous clouds. When the
ascending currents are powerful, they give rise to the _nuclei_, to the
_penumbrae_, to the _faculae_. If this explanation of the formation of
solar spots is well founded, we must expect to find that the sun does
not constantly emit similar quantities of light and heat. Recent
observations have verified this conclusion. But large nuclei, large
penumbrae, wrinkles, faculae, do they indicate an abundant luminous and
calorific emission, as Herschel thought; that would be the result of his
hypothesis on the