_Theophilus._ Yes, I know from your manuscript, and I had already known, that the stars which we see by night, but which the greater light of the sun hides from us in the day-time, are self-luminous orbs, each the centre of attraction and the lamp to the particular world it lights, and which revolves around it. As a whole company of planets, satellites, asteroïds, and comets revolve round our sun, receiving heat, motion, and light from that great central orb, so, the stars dispersed throughout space, communicate motion and activity to a vast aggregate of planets and satellites. These planets, which revolve round the stars, constitute _stellar worlds_, analogous to our solar world. We cannot see the planets, which accompany these stars, by reason of their smallness, and the prodigious distance between us and them, beyond the reach of the most powerful telescopes; we only see the suns which govern them, _i.e._, the stars. But the existence of the fixed stars, like our sun, implies the existence of planets revolving around them. _The Author._ Perfectly correct. Thus, our solar world is not unique, it is only one member of the family of stellar worlds, which resemble our world in the disposition and the motions of the stars within them. The universe is composed of the agglomeration of them all. You know all this, but there is one fact which, as it is the result of recent discoveries, you may not be aware of; it is, the great variety of disposition or of physical aspect presented by certain stars, in which a kind of overturn of that which constitutes nature on our globe has taken place. While they remain similar to our world in the order of their movements, certain stars differ widely in the forces which govern nature in them. _Theophilus._ Pray explain your meaning. _The Author._ While our solar system is governed by a single central star, there are stellar systems which are governed by two, three, and even four suns. It is evident that worlds which have two or three centres of light and heat must present physical and mechanical peculiarities of which we have no idea. There are also other differences proper to many of the stellar worlds. The light of our sun and of the greater number of the stars is constant: it never undergoes either augmentation or diminution. But this is not the case with many of those distant suns which we call stars. We see their light alternately fade and revive; sometimes they shine brightly, then become almost imperceptible, and anon brilliant again. Some of them become altogether extinct. The decrease in lustre of several stars has been noted by different astronomers.[23] Stars which have been observed in other times no longer exist.[24] Others have suddenly appeared, shone with excessive lustre, and at the end of some years have been seen no more.