THE GREAT EARTHQUAKE.

Pelorus Guardian and Miners' Advocate., Volume 8, Issue 26, 29 March 1907, Page 7

THE GREAT EARTHQUAKE.

AN EXTRAORDINARY THEORY

The two tremendous convulsions which within a fortnight have laid waste the enviprns of Vesuvius and temporarily wiped out of existence one of the greatest cities on the American continent have brought to the. front a theory of the cause of earthquakes and of volcanic action that presents our revolving globe to us in an entirely new and very startling light. According to this theory, the disasters referred to were caused by the earth, as it whirls on its 8,000-mile axis, getting a little off its centre, like an ill-balanced wheel, and striving, with a sudden shift, to recover Its equilibrium. It lias been known for a score of years past that the axis of rotation of the earth has what may best be described as a “wobble.” By carefully watching the direction of certain stars, astronomers have found that the ends of the earth’s axis do not always point towards exactly the same opposite spots in the sky, but swing about a little, thus introducing lost motion into the territorial mechanism. . When the axis sways out of its mean position the effect upon the earth must be similar to that produced in a balance wheel that is a little loose on its axis. A very sudden change of this kind would knock everything' to pieces on the surface of the earth, send the oceans roaring over the boarders of the continents. and involve the. whole force of the globe in ruin. The amount of departure never reaches more than about sixty feet as measured on the earth’s surface at one of the polos. This erratic motion, reacting upon the interior of the groat globe, must necessarily strain the subterranean rocks, thus producing volcanic eruptions and earthquakes. Professor John Milne, the distinguished expert in earthquake studios, is represented as urging this view in opposition to the generally accepted opinion of the gradual cooling and shrinking of its interior.

Hut the question then arises ; To what cause is the unbalancing of the earth, resulting in the wobbling of its axis, to be ascribed ? Sir Norman Lockyer tells us it is due indirectly to the present sun-spot maximum, which has vastly increased the amount of solar energy exerted upon the earth, and directly to the melting away of the snows about one of the earth’s poles consequent upon that increase of solar action.

This, it is averred, is sufficient to remove from its ordinary place about the pole a weight of ice and snow represented by incalcuable millions of tons. The water formed by melting is swept towards the equator through the oceans, in consequence of centrifugal (flying from the centre) tendency, and thus one end of the earth's surface is rendered sensibly lighter than the other, and a swinging and wobbling of the great axis results.

in view of this hypothesis it becomes interesting to inquire ; At which polo has the melting oft the ice occurred ? The reply plainly is ; At the South Pole, because the recent intense activity of the sun, as revealed by the presence of gigantic spots upon its surface, occurred during the summer of the Southern Hemisphere, at the time when the South Polar regions were presented towards the the sun, and also at a time when the earth was about three million miles nearer to the sun than it will be a few months hence.

That there may be truth in the idea that the solar radiation has been extraordinary effective in its action upon the vast accumulation of ice on the Antarctic continent is indicated by the fact that the past winter lias been one of universal mildness throughout the Northern Hemisphere. This being the case, we may well suppose that the corresponding summer in the Southern Hemisphere has been uncommonly hot.

it is to bo noted, in connection with the foregoing, that the unusual activity of the sun has not yet ceased, and that if it should continue during the coming summer to pour upon us an uncommon quantity of heat, the obvious consequence would be to molt away the Arctic ice and snow also, and thus, by removing weight from the northern axial end of the planet, to restore the balance, upset by what had occurred at the southern end. With this restoration the axis of rotation would tend to resume its mean position, although the change back again might result in fresh internal disturbances. Another theory is that of the more direct influence of

the sun spots.—“ Science Siftings.”