The Evacuation of England: The Twist in the Gulf Stream

by L. P. Gratacap

“This chart,” said the speaker, “presents to you the structural conception of Professors Jeans and Sollas, of the form of the earth. It is the shape more or less familiar to you, commonly known as a pear-shaped earth, the tip carrying the Sahara Desert on its bulging top, and its broader and inferior extremity holding the disturbed Pacific basin.

“Now it makes a very practical difference what the shape of the earth is, because the shape affects the stability, has an important influence upon the fluctuating strains under its surface. Observe that the chart has developed, upon two circles of instability, these lines of weakness,” and the lecturer swept his pointer over the contrasted belts, one around Africa, and the other inflicting the west coast of North America with its ominous intersection. The pointer paused on the latter circle, stopping near the position of San Francisco. “You recall,” the speaker continued, “the terrifying affliction of this great city in 1906, and the pall of discouragement and gloom which it cast over the region in which the city naturally held the sway of mercantile supremacy. Now it was shown by Prof. H. H. Turner, the English astronomer, that San Francisco lies on one of the two great earthquake rings, which surround the end of the pear, as in this chart, like wrinkles produced by the crowding down of the protuberances under the force of gravitation. And, according to this view, such rings, marking lines of weakness and yielding in the rocks would not exist, if the earth was, in its shape, what we most usually assume to be its figure, an oblate spheroid, with the present north and south poles at the ends of its axis of rotation, to which axis of rotation the rest of the earth was symmetrically disposed.

“The existence of these earthquake and volcanic rings was known before the pear theory had been defined, but then of course their relation with any peculiar form of the earth was not understood. The ring surrounding the Pacific, or butt end of the pear includes a large part of the shores of the Pacific Ocean, running from Alaska down to the western coast of South America, then across to the East Indies, and back, around the other side, through Japan. The other ring is somewhat smaller in diameter, including the earthquake regions of West Africa and the Atlantic Islands. Now the point of interest is this, as Garrett P. Serviss has significantly said, ‘If the pear hypothesis is accepted, and the two great earthquake rings are found to be definitely connected with the strains to which the planet is subjected in its effort to attain a state of equilibrium, under the forces of its own gravitation and rotation, which tend to compel it into spheroidal shape, then we have a perfectly rational explanation of the existence of certain places where earthquakes are sure to occur more or less frequently, and of other places, like eastern America, where they are very rare and never of maximum violence.’

“Every one present this evening,” and the lecturer gave an embracing wave of his hand, “knows of the singular aberrancy in the rotational motion of the earth, which has been often geographically described as the ‘wobbling of the poles.’ Astronomers have proven a real tipping of the poles alternately to one side, and then to the other, a swaying of the poles like the recurrent oscillations of a top as it ‘goes to sleep.’ But this swaying in the earth’s case is periodic and unchanging. It is sometimes rather abrupt, and at other times the tipping is regulated and progressive; but it is established, and has had a generally accepted explanation, in the attraction of the swelling equatorial prominence of the earth by the sun and moon, while suggestions have also been made that it was due to internal shiftings of mass, or to changes of exterior weightings, through the alternate and variable formation and melting of polar snows.

“But it has in the light of the present theory of the pear-shaped earth a new and rather startling explanation.

“We are, however, this evening, not so much concerned with the broader cosmic aspects of this state of affairs, as with the immediate consequences to the permanence of our land surfaces.

“The mechanics of this condition and its possible effectiveness in developing contrary placed zones of rupture can be easily conceived. This awkwardly conditioned sphere, revolving upon a shorter diameter—revolving also with astonishing velocity—and bearing at either extremity of its longer axis unequal masses, is obviously in a state of peripheral strain, that is, it is in strain at such distances from either of the disproportioned ends, the one in the south seas, the other in the desert of Sahara, as would represent the more or less sharply sloping surface from its average rotundity, towards these oblique extremities.

“Gentlemen,” the speaker seemed excitedly rushing into danger, but with a fixed expression, aimed somewhere at the blank and uninfluential physiognomies at the back of the hall; like that of an engineer who can neither restrain nor reverse the speed which may either carry him safely over a tottering support or plunge his train to the bottom of the gulch; “Gentlemen, the Isthmus of Panama is in this zone; the Canal is there!” this last reminder uttered with no very reasonable deliberation, “and it is to my mind an absolutely established certainty, that the secular instability of that region, shown by geological investigation, will again become apparent; and”—he raised his voice with a kind of exhalation of defiance, as if he spurned equivocation and invited denial—“and, it will become apparent with increased violence.

“This conclusion is unwelcome; it may seem destructive to those natural hopes which the approaching completion of this wonderful enterprise—the Panama Canal—have so freely and inevitably fostered. Science in the last resource to her councils must be austerely judicial. She cannot take cognizance of man’s projects or respect his hopes. The Panama Canal as part of the Isthmus of Panama participates in all the vicissitudes of the latter, and we know that those vicissitudes mean dislocation and subsidence. When such frightful results will happen, it is impossible to say; that they must happen, we can positively assert.”

The lecture was over. The lecturer retreated, and again repeated his deferential nod to the chairman, Dr. Smith, as if importuning his assistance in corroboration of his mournful vaticination. The audience still remained immobile, coagulated into a sort of mental prostration by this dismal prophecy, and yet again as if contemplating, like a cat’s stagnation, preparatory to its murderous spring, some outward and physical resentment. And the spring came.