* * * * * In 100 million years, the earth where we live will no longer exist, or if any wreck of it remains, it will only be a funereal desert. The various worlds of our system will have achieved their circle of life, the histories of its human race will long ago have been finished, our own Sun, no doubt, will have lost its light and will roll along a dark star, through the realms of night. It may be that, thrown back by destiny into the melting-pot of perpetual change, united in a supreme climax with some old dead sun traversing the same abyss, it will arise like a phœnix from its ashes by the conversion of motion into heat. But, then as now, the nebulæ will have given birth to suns, then as now, endless space will be filled with stars without number gravitating in the harmony of their mutual attraction, the planets will swing in the rays of their suns, mornings and evenings will follow each other, blue sky will spread overhead, clouds will float in the twilight mysteries, perfumed breezes will blow through the woods and valleys, mysterious sounds will stop the songs of the birds, and eternal love will sway a later youth with the divine rapture of insatiable aspirations. Marvellous ascension of life! Nature will chant, as it does to-day, the hymn of youth and happiness, and an imperishable spring will bloom for ever in this immense universe where the historian of the past sees nothing but tombs! If there are no limits to space, if, whatever part of the sky our thought may essay, it can always pass on without being stopped by anything, however swift or prolonged its flight, if, in a word, space is infinite in every sense, it is the same with eternity: there is no possible limit to it, and whatever end we may imagine, whatever hour or minute fixed for its end, our thought immediately leaps the obstacle and continues on its way. Infinity even now is filled with budding worlds, worlds reaching maturity, decadent worlds, dead worlds, disseminated in all regions of an unlimited space, gaseous nebulæ, hydrogen suns, oxidised stars, planets in the course of formation, congealed satellites, disintegrated comets--the forces of Nature are everywhere active, the energy of creation remains constant, neither increasing nor diminishing, and all the scientists agree in testifying that what we call destruction and annihilation is only transformation. Astronomy reveals to us Time as it has revealed Space. It shows that there is nothing peculiar about our present epoch in the history of Nature, nor about our present position in space, and it combines Time and Space, the two forms of reality, in the same synthesis as the two grand aspects of the development of the universe. * * * * *