2. THE NEGATIVE ACCELERATION. This phenomenon was observed to a greater or less extent all over the globe. It was especially marked near the equator; but in Northern Europe it was noted by only a few observers, though many clocks were stopped and other instruments deranged. There appears to be no doubt that a force of terrific magnitude was applied in a tangential direction to the surface of the earth, in such a direction as to oppose its axial rotation, with the effect that the surface velocity was diminished by about one part in three hundred, resulting in a lengthening of the day by five minutes, thirteen and a half seconds. The application of this brake--(_Bremsekraft_), as we may term it--caused acceleration phenomena to manifest themselves precisely as on a railroad train when being brought to a stop. The change in the surface speed of the earth at the equator has amounted to about 6.4 kilometres an hour; and various observations show that this change of velocity was brought about by the operation of the unknown force for a period of time of less than three minutes. The negative acceleration thus represented would certainly be too small to produce any marked physiological sensations, and yet the reports from various places indicate that they were certainly observed. The sensations felt are usually described as similar to those experienced in a moving automobile when the brake is very gently applied. 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.