"The Plurality of Worlds," now republished, is the most recent work of this description that has fallen under our notice. We can see no reason why an Essay of so much ability, in which the reasoning is so dispassionate, and opponents are treated so candidly, should appear anonymously. True, the author takes ground against some opinions widely maintained respecting the extent of the inhabited universe, and seems to suppose that he shall meet with little sympathy; and this may be his reason, though in our view quite insufficient, for remaining incognito. We think he will find that there are a secret seven thousand, who never have bowed their understandings to a belief of many of the doctrines which he combats, and he might reasonably calculate that his reasoning will add seven thousand more to the number. We confess, however, that though we have long been of this number to a certain extent, we cannot go as far as this writer has done in his conclusions. All the world is acquainted with Dr. Chalmers' splendid Astronomical Discourses. Assuming, or rather supposing that he has proved, that the universe contains a vast number of worlds peopled like our own, he imagines the infidel to raise an objection to the mission of the Son of God, on the ground that this world is too insignificant to receive such an extraordinary interposition. His replies to this objection, drawn chiefly from our ignorance, are ingenious and convincing. But the author of the Plurality of Worlds doubts the premises on which the objection is founded. He thinks the facts of science will not sustain the conclusion that many of the heavenly bodies are inhabited; certainly not with moral and intellectual beings like man. Nay, by making his appeal to geology, he thinks the evidence strong against such an opinion. This science shows us that this world was once certainly in a molten state, and very probably, at a still earlier date, may have been dissipated into self-luminous vapor, like the nebulæ or the comets. Immense periods, then, must have passed before any organic structures, such as have since peopled the earth, could have existed. And during the vast cycles that have elapsed since the first animals and plants appeared upon the globe, it was not in a proper condition to have sustained any other than the inferior races. Accordingly, it has been only a few thousand years since man appeared.