The most memorable seaquake of the Chilian coast was that of August 13th, 1868, when the coast of South America was shaken from Ecuador to Valdivia. In the town of Arica most of the buildings were thrown down. A few minutes later the sea began to retire slowly from the shore, so that ships anchored in seven fathoms of water were left high and dry. Then the sea returned like a great wall of water, which caught up the ships in the roadstead and swept them inland like chips of wood. Among them was the United States war vessel _Wateree_, which was carried inland nearly half a mile and was left, little injured, on dry land when again the wave receded. The wave of this catastrophe was felt far away from Chili. It was perceived on the coasts of Australasia, Japan, Kamchatka, Alaska, and California. In the harbour of Hakodate, in Japan, a series of waves was registered on the tide-gauge. The ordinary tide in that port is only about two and a half to three feet. On this occasion the water rose and fell a height of ten feet in twenty minutes. It had taken the first wave twenty-five hours to travel the distance of 7600 miles from South America. On May 9th, 1877, another seaquake almost as great as this was felt in many of the same places. This was on the occasion of the Iquique earthquake. At Arica the stranded hulk of the _Wateree_, which had remained high and dry for nine years, was picked up and swept farther inland. Like its predecessor, the wave was felt all over the Pacific. At Samoa the height of the waves varied from six to twelve feet; in New Zealand from three to twenty feet; in Japan from five to ten feet. When a wave reaches shallow water it piles itself up to a height, as any one knows who has watched the waves coming in on the sea-shore, so that the height of a wave measured on the tide-gauge of a seaport is a good deal greater than that of the height of the wave when it is far out on the ocean. In fact, the mid-ocean height of the wave is likely to be inches while the in-shore wave is measured in feet. An illustration of this can be seen on the coast of Cornwall, where sometimes, on quite a calm day the sea that looks so still breaks on the shore in big rollers. We cannot tell exactly how high an earthquake wave may be in mid-ocean, but we know it cannot usually be very great, though it travels at great speeds--sometimes as much as five miles a minute, or three hundred miles an hour.