Page:Popular Science Monthly Volume 25.djvu/386

374 Island, and plunged it into the sea some seven miles to the northeast, where Calmeyer Island now blocks the channel which mariners have known so long as the East Passage.

The reports we have as to the tidal phenomena differ from different places. At many points it was observed that a distinct withdrawal of the water preceded the rise or great tide; while from others, as in the canal at Batavia, the opposite is given as the order of occurrence. Everything, however, depends on the moment of the observation. It will be apparent that these waves were the most natural consequents of the events, and were due certainly not to any seismic movement of the sea-bed, but, on the one hand, to the in-rush of water to fill the deep chasms out of which the ejected portions of the island came, which was naturally followed first by a withdrawal of the water, and then by a disastrous recoil over the low fore-shores of Java and Sumatra; and on the other hand to the tremendous stroke—the splash, in fact—imparted to the sea by such a gigantic block of matter, square miles in size, which must have resulted first in a great rise of water, followed by a withdrawal.

It is a remarkable circumstance that in the logs of several ships which were in the close vicinity of the volcano in the forenoon of the 27th, no mention is made of the great wave which proved so destructive, and which could scarcely, one conceives, have failed to attract attention. May the explanation not lie in the supposition that these two great waves—the in-rush and the splash waves—which would follow each other after a short interval, had neutralized each other at the spots where these vessels chanced to be at the moment? Issuing from the narrow straits into the oceans east and west, these waves started off on their journey round the globe, and, from the records of the tide-gauges which are now coming in, we have a most remarkable tale unfolded. On the afternoon of the same day that the greater of them swept away the Javan villages, the undulations were registered unmistakably in Mauritius, the Seychelles, in South Africa, and on the shores of the Pacific islands; but, as Mr. Lockyer informs us, they did not vanish there, but proceeded onward, and, crossing each other on the antipodes of Krakatau, journeyed back to the spot whence they had emanated, and this they did no fewer than four times before the equilibrium of the sea was restored so far as to be insensible to our instruments. While the tide-gauges have recorded their story, the delicate fingers of the barometrical registers of the world have also borne uninfluenced testimony of a similar kind. The blow which hurled such a mass of matter into the air, which originated a hurricane there and caused the barometers in the neighborhood of the volcano to rise and fall with unparalleled rapidity and a vessel distant three hundred miles to tremble, started an atmospheric wave also round the globe. It was first detected in the Kew registers, we believe, by General Strachey, who has now