Page:Popular Science Monthly Volume 18.djvu/36

26 is more certain than that the contraction of the sun, from a diameter even many times larger than that of Neptune's orbit to its present dimensions, if such a contraction has actually taken place, has furnished about eighteen million times as much heat as the sun now supplies in a year; and, therefore, that the sun can not have been emitting heat at the present rate for more than that length of time, if its heat has been generated in this manner. If it could be shown that the sun has been shining as now for a longer time than that, the theory would be refuted; but, if the hypothesis be true, as it probably is in the main, we are inexorably shut up to the conclusion that the total life of the solar system, from its birth to its death, is included in some such space of time as thirty millions of years: no reasonable allowances for the fall of meteoric matter, based on what we are now able to observe, or for the development of heat by liquefaction, solidification, and chemical combination of dissociated vapors, could raise it to sixty millions.

At the same time it is, of course, impossible to assert that there has been no catastrophe in the past—no collision with some wandering star, endued, as Croll has supposed, like some of those we know of now in the heavens, with a velocity far surpassing that to be acquired by a fall, under the sun's attraction, even from infinity—producing a shock which might in a few hours, or moments even, restore the wasted energy of ages. Neither is it wholly safe to assume that there may not be ways of which we yet have no conception, by which the energy apparently lost in space may be returned, and burned-out suns and run-down systems restored; or, if not restored themselves, be made the germs and material of new ones to replace the old.

But the whole course and tendency of things, so far as science now makes out, points backward to a beginning and forward to an end. The present order of things appears to be limited in either direction by terminal catastrophes, which are veiled in clouds as yet impenetrable.



HERE can not be two opinions as to the prejudicial influence exerted upon the industrial interests of Great Britain by the unsatisfactory state into which the question of apprenticeship has been gradually drifting, and out of which it has not yet begun to rise anew. Out of harmony with the necessities and conditions of the times, a relic of days long past, ere the steam-engine, or perhaps even the 