Moreover, certain destructive actions are reported from localities near the equator—chimneys fell and tall buildings swayed; while from New York comes the report that the obelisk in Central Park was thrown from its pedestal. It appears that these effects were due to the circumstance that the alteration of velocity was propagated through the earth as a wave similar to an earthquake wave, and that the effects were cumulative at certain points—a theory that is substantiated by reports that at certain localities, even near the equator, no effects were noted.
3. Tidal Waves. These were observed everywhere and were very destructive in many places. In the Panama Canal, which is near the equator and which runs nearly east and west, the sweep of the water was so great that it flowed over the Gatun Lock. On the eastern coasts of the various continents there was a recession of the sea, the fall of the tide being from three to five metres below the low-water mark. On the western coasts there was a corresponding rise, which in some cases reached a level of over twelve metres.
That the tidal phenomena were not more marked and more destructive is a matter of great surprise, and has been considered as evidence that the retarding force was not applied at a single spot on the earth's surface, but was a distributed force, which acted on the water as well as on the land, though to a less extent. It is difficult, however, to conceive of a force capable of acting in such a way; and Björnson's theory of the magnetic vortex in the ether has been rejected by this commission.
4. Atmospheric Disturbances. Some time after the appearance of the yellow aurora a sudden rise in atmospheric pressure, followed by a gradual fall considerably below the normal pressure, was recorded over the entire surface of the globe. Calculations based on the time of arrival of this disturbance at widely separated points show that it proceeded with the velocity of sound from a point situated probably in Northern Labrador. The maximum rise of pressure recorded was registered at Halifax, the self-recording barographs showing that the pressure rose over six centimetres in less than five minutes.
5. Shift in Direction of the Earth's Axis. The axis of the earth has been shifted in space by the disturbance and now points almost exactly toward the double star Delta Ursæ Minoris. This change appears to have resulted from the circumstance that the force was applied to the surface of the globe in a direction not quite parallel to the direction of rotation, the result being the development of a new axis and a shift in the positions of the poles, which it will now be necessary to rediscover.
It appears that these most remarkable cosmic phenomena can be explained in either of two ways: they may have resulted from an explosive or volcanic discharge from the surface of the earth, or from the oblique impact of a meteoric stream moving at a very high velocity. It seems unlikely that sufficient energy to bring about the observed changes could have been developed by a volcanic disturbance of the ordinary type; but if radioactive forces are allowed to come into play the amount of energy available is practically unlimited.
It is difficult, however, to conceive of any way in which a sudden liberation of atomic energy could have been brought about by any terrestrial agency; so that the first theory, though able to account for the facts, seems to be the less tenable of the two. The meteoric theory offers no especial difficulty. The energy delivered by a comparatively small mass of finely divided matter, moving at a velocity of several hundred kilometres a second—and such a velocity is by no means unknown—would be amply sufficient to alter the velocity of rotation by the small amount observed.
Moreover, the impact of such a meteoric stream may have developed a temperature sufficiently high to bring about radioactive changes, the effect of which would be to expel helium and other disintegration products at cathode-ray velocity—(Kathoden-Strahlen-Fortpflanzung-Geschwindigkeit)—from the surface of the earth; and the recoil exerted by this expulsion would add itself to the force of the meteoric impact.
The presence of helium makes this latter hypothesis not altogether improbable, while the atmospheric wave of pressure would result at once from the disruption of the air by the passage of the meteor stream through it. Exploration of the region in which it seems probable that the disturbance took place will undoubtedly furnish the data necessary for the complete solution of the problem." [Pp. 17-19.]