If the earth should fall into the sun, it would make good for ninety-five years the actual loss of solar energy; Venus would make good this loss for eighty-four years; Mercury for seven; Mars for thirteen; Jupiter for 32,254; Saturn for 9652; Uranus for 1610; and Neptune for 1890 years. That is to say, the fall of all the planets into the sun would produce heat enough to maintain the present rate of expenditure for about 46,000 years. It is therefore certain that the fall of meteors greatly lengthens the life of the sun. One thirty-third millionth of the solar mass added each year would compensate for the loss, and half of this would be sufficient if we admit that condensation shares equally with the fall of meteorites in the maintenance of solar heat; centuries would have to pass before any acceleration of the planets’ velocities would be apparent. Owing to these two causes alone we may, therefore, admit a future for the sun of at least twenty million years; and this period cannot but be increased by other unknown causes, to say nothing of an encounter with a swarm of meteorites. The sun therefore was the last living member of the system; the last animated by the warmth of life. But the sun also went out. After having so long poured upon his celestial children his vivifying beams, the black spots upon his surface increased in number and in extent, his brilliant photosphere grew dull, and his hitherto dazzling surface became congealed. An enormous red ball took the place of the dazzling center of the vanished worlds. For a long time this enormous star maintained a high surface temperature, and a sort of phosphorescent atmosphere; its virgin soil, illumined by the light of the stars and by the electric influences which formed a kind of atmosphere, gave birth to a marvelous flora, to an unknown fauna, to beings differing absolutely in organization from those who had succeeded each other upon the worlds of its system. But for the sun also the end came, and the hour sounded on the timepiece of destiny when the whole solar system was stricken from the book of life. And one after another the stars, each one of which is a sun, a solar system, shared the same fate; yet the universe continued to exist as it does today. Ψ The science of mathematics tells us: “The solar system does not appear to possess at present more than the one four hundred and fifty-fourth part of the transformable energy which it had in the nebulous state. Although this remainder constitutes a fund whose magnitude confounds our imagination, it will also some day be exhausted. Later, the transformation will be complete for the entire universe, resulting in a general equilibrium of temperature and pressure.