Let us follow in imagination the travels of one such comet through the untold ages of its life. It may have started on its tremendous voyage whilst the earth was yet a star, or rather a miniature sun, instinct with fire and light, and all through the long ages during which the earth was cooling down and becoming fitted to be the habitation of living things, the comet slowly but steadily pursued its way. On the earth one form of life succeeded another, the sea overcame the land time after time, and time after time the continents flung off the yoke, and emerged with ampler borders and fairer scenes. At length the predestined prince came to his heritage, and Man was made ruler over the perfected earth—too soon, alas! to forfeit his vice-regal crown by an act of flagrant rebellion. And still through all these ages, compared with which the whole lifetime of our race is but a moment, that distant comet held on its course, never swerving by a hair’s breadth from the appointed path, obedient to the law, the self-same law that decrees the fall of the ripened fruit. But it was still far away, and still it pressed slowly but steadily forward, whilst kingdoms rose and fell, and nations multiplied and decayed. But gradually a quicker energy began to throb within it, and a stronger impulse drew it forward. The old slow pace could not suffice for its growing impatience, and it pressed forward with ever-increasing speed. At length it dashes across the orbit of Neptune; it has entered the solar system at last. No lingering now, no slow and halting pace; quicker and quicker it presses on, and Uranus is past. A shorter interval still, and glorious Saturn, with his noble rings and numerous satellites, is left behind, and a few years more and it shoots across the path of the giant planet Jupiter. The asteroids and Mars are passed by next, and now, filled with a passionate desire, it whirls along, brightening as it speeds, and flaming streamers flying behind it. Moving more quickly still, it crosses the orbit of the Earth. Venus is reached next; traversing now in a moment of time space it once took a year to travel over, it rushes past Mercury. And now the bright goal is at hand, and quivering through all its mighty length with the fierce excitement, it speeds forward at a swifter pace still. And now, glorious with jets streaming ten thousand miles before it, and tail ten million leagues behind, it hurls itself into the corona, the region of that strange pearly glow which in total eclipses is seen to surround the Sun. And still it hurries forward, but not into the Sun, its headlong speed is now far too great for even that mighty attraction to be able to check it in its course, and draw it in to itself. It ploughs its way perhaps even at the rate of a million miles an hour, round nearly half of the circumference of the sun, through the regions where the prominences play—those rosy flames that rise and rush with such terrific heat and