Assuming such a resisting medium, these wandering ce-
lestial bodies must have oa the periphery of the solar system
their cradle, and in its centre their grave ; aJid however long
the duration, and however great tbe number of their revolu-
tions may ba, as many masses will on the average in a cer-
tain time arrive at the sun as formerly in a lilie period of
time caoie within his sphere of attraction.
All these bodies plange with a violent impetus into their
common grave. Since no cause exists without an effect, each
of these cosmical masses wUI, lite a weight falling to the
eartii, produce by its percussion an amount of beat propor-
tional to its vis viva.
IVom the idea of a sua wtose attraction acts throughout
space, of ponderable bodies scattered tiiroughout the universe,
and of a resisting lether, another idea necessarily follows —
that, namely, of a continual and inexhaustible generation of
heat on the central body of this cosmical system.
Whether such a conception be realized in our solar system
— ^whether, in other words, the wonderful and permanent evo-
lution of light and heat be caused by the uninterrupted faU
of cosmical matter into the sun — will now he more closely
examined.
