magnesium, and sundry other bodies in the sun, and of several of the same in the fixed stars and the nebulæ. There is little uncertainty about these determinations. Like an expert who identifies the handwriting of a criminal when he who penned it may have fled a thousand miles away, this little instrument, by an analysis of light that has wandered a thousand years away from its source, declares the nature of the luminous body that sent it forth. One sort of matter exists throughout all the wide realm which human vision has traversed.

One ether extends through all. The conditions under which light is propagated are identical upon Sirius and in the apartment lighted by a jet of

gas.

Gravitation reigns over all. The phenomena discerned in the motions and phases of the stars and the nebulæ are such as attest the dominance there of the same law as holds the earth in its orbit, or guides an apple to the ground.

The law of rotation reigns over all. From the revolving moon to the vicissitudes of the variable stars-winking night and day in regular alternation-and even to the spiral nebula whose stupendous gyrations have given shape to their flowing vestments-every where the equilibrium of celestial bodies, like that of a top or a gyroscope, is maintained by rotation.

Our own firmament of stars, which we are not permitted to view as we view the nebulæ, from a distance, reveals even to a beholder from within the fact of its rotation, as the progress of a sloop upon a river is revealed by the apparent motions of the trees upon the banks. Mädler has announced the discovery of the astounding fact that the entire firmament is describing a slow and majestic gyration about a centre which, to us, seems located in the Pleiades. In this common whirl of a million suns our sun participates, and, with his retinue of planets, moves forward

through space at the rate of one hundred and fifty millions of miles a year. And yet so vast is the circuit upon which he is launched that 18,200,000 years will have faded away before he shall have completed a single revolution.

If throughout all these boundless intervals of space a resisting ether is present-if it be a fact that a material fluid pervades all the wide realms which light has traversed, what is the conclusion which looms up as a consequence? Are we not compelled to recognize the fact that every sun in our firmament, as it journeys round and round in its circuit of millions of years, is slowly, but surely as Encke's comet, approaching the centre of its orbit? And in that most distant future, the contemplation of which almost paralyzes our powers of thought, is it not certain that all these suns must be piled together in a cold and lifeless mass? I forbear to say more. With reverence I refrain from the attempt to lift the veil which conceals the destiny of other firmaments. I dare not hazard the inquiry whether an immensity of firmaments may not be executing their grand gyrations on a still larger scale; and whether these, in turn, may not be destined to a grander cosmical conglomeration. It is vain to push our conjectures farther. We have even here entered upon the border-land of infinite space. In the presence of Infinity, what can man do but bow his head and worship?

Reason assures us that somewhere the tendency to central aggregation must be stayed. A universe of worlds can never be gathered together in a single mass. Within the bounds of the visible we. see all matter wending its way toward centres of gravity. Within the bounds of our firmament we see all matter tending toward one centre. Let us content ourselves to speak of this. This shall be our universe. This is the universe whose final aggregation into one mass we are compelled to contemplate.

magnesium, and sundry other bodies in the sun, and of several of the same in the fixed stars and the nebulæ. There is little uncertainty about these determinations. Like an expert who identifies the handwriting of a criminal when he who penned it may have fled a thousand miles away, this little instrument, by an analysis of light that has wandered a thousand years away from its source, declares the nature of the luminous body that sent it forth. One sort of matter exists throughout all the wide realm which human vision has traversed.

One ether extends through all. The conditions under which light is propagated are identical upon Sirius and in the apartment lighted by a jet of gas.

Gravitation reigns over all. The phenomena discerned in the motions and phases of the stars and the nebulæ are such as attest the dominance there of the same law as holds the earth in its orbit, or guides an apple to the ground.

The law of rotation reigns over all. From the revolving moon to the vicissitudes of the variable stars-winking night and day in regular alternation-and even to the spiral nebula whose stupendous gyrations have given shape to their flowing vestments-every where the equilibrium of celestial bodies, like that of a top or a gyroscope, is maintained by rotation.

Our own firmament of stars, which we are not permitted to view as we view the nebulæ, from a distance, reveals even to a beholder from within the fact of its rotation, as the progress of a sloop upon a river is revealed by the apparent motions of the trees upon the banks. Mädler has announced the discovery of the astounding fact that the entire firmament is describing a slow and majestic gyration about a centre which, to us, seems located in the Pleiades. In this common whirl of a million suns our sun participates, and, with his retinue of planets, moves forward

through space at the rate of one hundred and fifty millions of miles a year. And yet so vast is the circuit upon which he is launched that 18,200,000 years will have faded away before he shall have completed a single revolution.

If throughout all these boundless intervals of space a resisting ether is present-if it be a fact that a material fluid. pervades all the wide realms which light has traversed, what is the conclusion which looms up as a consequence? Are we not compelled to recognize the fact that every sun in our firmament, as it journeys round and round in its circuit of millions of years, is slowly, but surely as Encke's comet, approaching the centre of its orbit? And in that most distant future, the contemplation of which almost paralyzes our powers of thought, is it not certain that all these suns must be piled together in a cold and lifeless mass?

I forbear to say more. With reverence I refrain from the attempt to lift the veil which conceals the destiny of other firmaments. I dare not hazard the inquiry whether an immensity of firmaments may not be executing their grand gyrations on a still larger scale; and whether these, in turn, may not be destined to a grander cosmical conglomeration. It is vain to push our conjectures farther. We have even here entered upon the border-land of infinite space. In the presence of Infinity, what can man do but bow his head and worship?

Reason assures us that somewhere the tendency to central aggregation must be stayed. A universe of worlds. can never be gathered together in a single mass. Within the bounds of the visible we. see all matter wending its way toward centres of gravity. Within the bounds of our firmament we see all matter tending toward one centre. Let us content ourselves to speak of this. This shall be our universe. This is the universe whose final aggregation into one mass we are compelled to contemplate.

OF

CHAPTER XL.

THE CYCLES OF MATTER.

F what, now, is this stupendous result the consequence? This is the goal toward which, for millions of ages, the forces of matter have been struggling. During every moment of this long history, gravitation has striven to draw these myriads of worlds together. They have embraced each other at last, and gravitation has retired to slumber. While yet these worlds were in active life, every sun was a heated globe, dispensing warmth through infinite space; and every planet may have been the seat of life, enjoying the boundless munificence of heat. As long as heat remained to be dispensed to planetary orbs, they were the seat of all those myriad activities of which solar heat is the origin and source-currents in the atmosphere and in the waters-ascending vapors and descending rainsthe nurture of vegetable and animal life and motions-the disintegration of continents, and the strewing of ocean bottoms with layers of sediments for the upbuilding of new continents. Through numberless interactions of heat, and electricity, and light, and magnetism, and mechanical forces, and chemical affinity, the web of material and organic history was woven. The equilibrium of the heat of our universe has now been attained. No farther interactions and transformations can ensue. Every particle of matter is equally cold. Every corner of space is equally dark. The electricities that have been worried with disturbances and divorces innumerable are now firmly locked in each other's embraces. Every chemical element has united with its