Abstract
A PLEASANTLY written and interesting work, spoiled by being coupled with a preposterous theory. Mr. Mossman boldly attempts a difficult task. He proposes to solve a complex problem on very simple principles. Unfortunately his principles are unsound; and overlooking this, there remains the objection that they do not solve his problem. This problem is the well-known fact that in bygone ages plants existed in high latitudes—as far north as England, for example—whose analogues are now only found in the tropics. Mr. Mossman explains this very simply. The obliquity of the ecliptic is now slowly decreasing; therefore it must once have been increasing, and doubtless—though astronomy objects—there was at one time no obliquity: in those days perpetual spring reigned on the earth. But there began a series of upheavals, he says, “directed chiefly towards the northern hemisphere almost exclusively,” and this hemisphere becoming overweighted, naturally began to incline. The inclination became at length perhaps twice as great as at present, or even more; but then the southern hemisphere began in its turn to be upheaved, and so checked the increase of inclination, and caused the present process of slow decrease. Mr. Mossman thinks there is nothing in this “contrary to the universal law of gravitation,” an opinion which he would modify were he more familiar with that law. The want of balance he speaks of would affect precession and nutation, but not the inclination of the earth's axis. Supposing gravity were on his side, however, and we granted his extension of the tropics, he should remember that the Arctic regions would be equally extended. If he brings the northern tropic to the latitude of London, he has brought the Arctic circle to the latitude of Madrid. Tropical plants in the latitude of Paris, say, would fare ill under this arrangement.
The Origin of the Seasons.
By Samuel Mossman. (Edinburgh: Blackwood & Sons. 1869.)
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The Origin of the Seasons . Nature 1, 260 (1870). https://doi.org/10.1038/001260a0
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DOI: https://doi.org/10.1038/001260a0