68 Sidereal Astronomy. [January, 
all this to be by us useless ? Shall we declare all this super- 
fluous, and perhaps even wearisome ? We ! the atoms of 
an atom ; we, blind gropers in the dark ; we, ignorant 
dwellers in a cave, who will only believe in the existence of 
the pale mushrooms which surround us ! By what name 
can designate such pretension ? Moreover, this is possibly 
the reasoning which is indulged in on other planets, where 
they declare that the earth must be uninhabitable because 
it is too cold (supposing it to be the inhabitants of Mercury 
who talk), or because it is too hot (supposing it be the Jovian 
inhabitants who hold forth). Poor Earth ! a microcosm 
invisible to Jupiter ; lost, like a little spot on the sun, to 
Saturn and the other exterior planets ; unknown to all the 
other solar systems of infinity ; — who would believe that it is 
still declared the queen of creation ? The queen, did I say? 
Who would believe that, as at the time of Joshua, we even 
now persuade ourselves that we are alone in the universe, 
and that nothing exists beyond our narrow boundaries ? 
This is not our mode of reasoning. On the contrary, 
without doubting for a moment that the stars, the suns of 
space, may be, in general, the centre of planetary systems 
more or less different from ours, we shall here discuss the 
novel conditions of worlds governed and illuminated by 
many suns, of different masses, different volumes, and dif- 
ferent colours. 
What is the character of the orbits described by the 
worlds belonging to these singular systems? Do these un- 
known planets turn round the two suns as their common 
centre ? and have they, as the focus of their movements, 
the centre of gravity of the twin suns ? or, rather, has each 
of the two suns its proper planetary system ? This last 
should be most probable and most general. 
Notwithstanding the essential difference which exists be- 
tween these systems and ours, we can, however, make use 
of the disposition of our system to divine the possible 
arrangement of the others. Already in our system one 
planet surpasses all the others in its volume, and without 
doubt also in its intrinsic heat, and it forms the centre of a 
little system of four moons, which it carries with it during 
its eleven years’ revolution round the sun. Let us suppose 
that Jupiter, which is already 1400 times larger than the 
Earth, was of a still more considerable volume, and shone 
with a blue light ; this supposition alone would modify our 
planetary system to the extent of creating three species of 
worlds: — First, four globes (the satellites of Jupiter), one of 
which is larger than the planet Mercury, illuminated and 
