Others go still farther, and imagine that life only appears on Earth, and that we have no sufficient reason to suppose that on other globes it has been the result of inorganic evolution. This, as we have often repeated, would be a strange interpretation of the language of Nature, considering that our small planet is too small a cup to contain the whole of life, that that life abounds everywhere, fills the waters, swarms in the air, covers the entire surface of the globe, and that the fertility of Nature is such that she multiplies parasitic life at the expense of life itself, rather than get tired of producing. And the spectacle is the same for all the immense duration of the geological eras. Quite lately, noticing a heap of fossils of the secondary era by the roadside in the country, I took a stone to put it into a collection, for it was entirely made up of shells petrified and cemented in a block. In taking it up I exposed a swarming mass of living beings, small snails, wood-lice, beetles; and I caught two lizards; while butterflies laid their eggs in the plants around. Life of former days, life of to-day, life everywhere. Life always! Certain minds are capable of supposing that for the whole duration of its existence, for millions of years, a world could come to nothing but the state of dead and barren rock and that the life which swarms on the surface of our planet is only a freak due to the fortuitous combination of elements of fruitfulness, a parasitism of more or less large fleas which might never have been produced at all. But that is a hypothesis contrary to the observation of Nature, and difficult to maintain seriously except as a pure play of the imagination, which does not satisfy the most elementary logic. And though our logic may not be that of Nature, yet we must not stray too far away from it if we want to reason. But as we have already repeated so often in this book, and what we must thoroughly absorb, is the importance of time as well as of space. Just as our world is nothing but a small island, a point in the universe, so also our era is nothing but a moment in eternity. The present moment has no more importance than the moments which have preceded or those which are to come. There is no reason to believe that such and such other worlds are inhabited at present simply because we live at present and can observe them. One world has been inhabited in the past, another will be inhabited in the future. Let us not be personal, like infants or the aged, who see only their own room. Let us know how to live in the infinite and in the eternal. INDEX Alpha Centauri, 38, 42 Andromeda, 70, 85 Animalculæ, 165 Atmospheres, planetary, 105 Atoms and stars, 157 Aurora Borealis, 175 Bernoulli, 166 Bessel, 100 Bode, 188 Champollion, hieroglyphics, 143 Cherbourg, 97 Communication, interplanetary, 141 Earth currents, 135 Eiffel Tower, 164 Electrons, 137 Fontenelle, 184