the silver coin which bore the image and superscription of Alexander, and wondered why I had called it venerable. Why? since twenty populations had possessed the earth, since the relics of those bucklered fishes had been animate, and this coin-why, it had been stamped in the last part of the lifetime of the twentieth population; and there were nineteen before it which had become extinct.

And so my feet were lifted up from earth; I was pillowed upon a bright cloud, and floated in eternity. And I saw the long history of the world I had left stretching backward from the spot where I had left it, till it vanished from view, like the track of a railroad on the boundless prairie. With the flash of a thought, I pursued it over millions of ages, till I saw it dissolved in fire-till luminous vapors rolled up and rested upon the bosom of infinite space. In this cloud of fire the track of terrestrial history lost itself, and I dared not plunge through the flame in search of a beginning.

Then I thought, here at length is the dwelling-place of antiquity. What is this which men call ancient and venerable? Would that the scales could be removed from our eyes! Would that the fog would lift, and men could once look out upon the magnitude of the universe-the majestic span even of terrestrial history-the might, the greatness, the wisdom, the glory of that Intelligence which, at a glance, takes in all space, all time past, and all time to come!

L

CHAPTER XXXIX.

THE MACHINERY OF THE HEAVENS RUNNING DOWN.

ET the earth have frozen; let the bright sun have been extinguished; let the moon and stars "wander darkling in the eternal space." Will this, then, be the end of matter's history? Is this the consummation of which philosophers, and poets, and patriarchs have dreamed and prophesied? From the pinnacle on which we stand we can discern the course of Nature still wending onward. There must be progress even after the funeral of the sun. As that bright luminary shines on after the fall of generations of men—as he shines serenely and undisturbed even in dead men's faces, so will gravitation continue to prosecute its work even among the corpses of planets and suns.

Hark! from the highways of the comets come tidings of friction in the machinery of the heavens. The filmy wanderer encounters resistance in his long journey to the confines of the solar system. He plows his way through a resisting medium. The balance of centripetal and centrifugal forces is destroyed; the central attraction preponderates; he falls toward the sun; his orbit is diminished; his motion is accelerated, and he comes back to his startingpoint earlier than the time which astronomy had appointed. Here we get the first disclosure of the existence of a subtile material fluid pervading space.

This remarkable retardation was first observed in the successive returns of Encke's comet. This comet has at present a period of about 1210 days, and it returns each time two hours and forty-five minutes sooner than calcula

tion requires. Since 1789, its period has shortened two days and sixteen hours. Similar retardation-resulting in a similarly accelerated angular velocity-has been fully established in the cases of the comets of Brorsen, Faye, and D'Arrest.

The only explanation that has ever been offered of these exceptional phenomena is the assumption of the existence of an all-pervading resisting medium commonly called ether. Since the undulatory theory of light became established, the existence of such a medium has been recognized as necessary, and its presence has been assumed throughout all those realms of space to which light has penetrated.

A belief in the existence of an all-pervading ether is much more ancient than the observations which have made it a scientific datum. In the astronomy of the Brahmins, the stars are said to swim in ether, as fishes in the water. Kepler supposed comets to be native inhabitants of this ethereal medium, like fishes in the sea. The Cartesian doctrine of "vortices" presupposes an all-pervading material fluid. The existence of such a fluid was admitted by Newton; and he demonstrates that its tenuity must be greater than that of our atmosphere at the distance of two hundred miles from the earth. In more recent times this doctrine has been maintained or admitted by Whewell, Sir John Herschel, Thompson, Mayer, Littrow, Helmholtz, Grove, Tyndal, Watson, McCosh, Comte, Rorison, and, in short, by every physicist who has investigated the subject.

We are compelled, then, to assume the position that a resisting fluid permeates space, and that the heavenly bodies do not move in a vacuum. The consequences of this admission are stupendous beyond conception. Laplace demonstrated that if the planetary bodies are solid, and if they move in vacuo, their mutual perturbations, in long cycles, compensate each other, and the stability of the solar sys

tem is perfect. The contingent part of this proposition. possesses all the significance. Neither are the planetary bodies solid, nor do they move in vacuo. The effect of the terrestrial liquids is apparent in a considerable lengthening of the sidereal day-which, for the time being, is counterpoised by the shrinkage of the earth-while the effect of the resisting medium has been wrought out in the partial arrest of the whole brood of comets.

The retardation of Encke's comet is such that it would lose one half of its present velocity in 23,000 years. A power which can sensibly check the flight of the filmy comet can also retard, however minutely, the motion of the ponderous planet. Jupiter, by far the largest of the planets, would lose one thousandth of his velocity in seventy millions of years. The length of the period has nothing whatever to do with the result. If the motion be inevitably and perpetually toward precipitation into the sun, the event is as demonstrable as the fall of an aerolite to the earth. Not only are the cloud-like comets slowly approaching the sun in spiral curves, but every revolving planet-every material particle in the solar system-is borne forward by the same unalterable decree. It is the presence of a resisting ether which conditions the precipitation of that meteoric rain which retards the cooling of the sun. The fall of comets and planets to the sun will still farther delay the final refrigeration of that luminary, without averting it.

The proof of the existence of a resisting ether in space has disclosed the decree which records the doom of the solar system. Whewell says: "Since there is such a retarding force perpetually acting, however slight it be, it must in the end destroy all the celestial motions. * * * The moment such a fluid is ascertained to exist, the eternity of the movements of the planets becomes as impossible as a

perpetual motion on the earth." Helmholtz says: “A time will come when the comet will strike the sun; and a similar end threatens all the planets, although after a time the length of which baffles our imagination to conceive it." Mayer contemplates the precipitation of asteroidal and planetary masses upon the sun. Comte says: "In a future too remote to be assigned, all the bodies of our system. must be united to the solar mass, from which it is probable that they proceeded." Rorison, defending the Mosaic account of creation, admits, speaking of the earth: "It was once all nebula; it will yet, if left to physical agencies, collapse into an exhausted and extinguished sun." Watson says: "If we grant that the retardation of the comets arises from the existence of an ethereal fluid, the total obliteration of the solar system is to be the final result."

This, then, is the conclusion of science. So far as we have been able to acquaint ourselves with the laws which regulate the movements of the planetary bodies, the duration of the present order of the solar system is finite. Nothing but an infinite miracle can save it from destruction. That such a miracle will be wrought we have no warrant for assuming. From the very beginning of its career, so far as we can judge, the history of matter has been wrought out in accordance with methods which we style the "laws of Nature." These methods have never been abandoned, and there is not a particle of evidence. furnished by science that they ever will be abandoned un-· til they shall have completed their work. Whether the forces of matter be viewed as inherent powers or as "immediate divine agency," the argument from induction, in which the doctrine of a final catastrophe rests, is an argument possessing strength beyond the power of arithmetic to express.

It is true that the final catastrophe is removed to the