Page:Popular Science Monthly Volume 13.djvu/363

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It will readily be seen, from previous considerations, that large masses of the resulting nebula will be thrown out from the sphere of sensible attraction of the remaining mass, with velocities exceeding 300 miles a second, while other portions will emerge with less and less velocities, till finally some portions barely reach those limits.

The remaining nebula should then begin to contract, and might, possibly, form a small planetary system. Of the out-thrown masses, those which moved with the greatest velocity would retire to the greatest distances; but even they must finally stop, because they could not overcome perpetual resistance.

The resistance which these masses have to contend with is of two kinds: first, the feeble, insensible attraction of the remaining mass; second, the resistance of the ether.

The first diminishes with the square of the increasing distance, but is never reduced to absolute zero; the second, however, diminishes with the diminishing speed, and finally becomes nothing, at which time the body stops.

Now, would these farthest masses return? Most certainly they would; for no distance can be named so great that the force of gravity shall become absolutely nothing.

If it took millions of years for the most distant body to move one inch, after it had stopped it would eventually return to the central mass, which would itself finally become quiescent.

It will be readily seen that if any number of such bodies were put in motion in the boundless ether, they, too, would finally come to rest.

Another very well-known and much shorter path leads to this same conclusion; it is this:

If the ponderable moving matter of the universe be limited, then, by constant collision, its motion would all be converted into heat and light, and be radiated into the outer realms of space, never to return again, leaving all the ponderable matter to collect into one great mass, and to cool off to a state of perfect quiescence.

But, if matter be infinite, then there can be no "outer realms" into which this heat-force can radiate; consequently there will be no motion lost, and matter, since it has ever been moving, will continue in motion forever.



IN executions it is the custom to drop the condemned man from a height, or (as in New York) to jerk him up from the ground by the fall of a heavy weight, so that there is a powerful concussion of the brain to start with. It used to be a common belief that the necks of