Even on the high seas the shock was felt no less distinctly than on dry land. “Off St. Lucar,” says Sir Charles Lyell, “the captain of the ship Nancy felt his vessel so violently shaken, that he thought she had struck the ground, but, on heaving the lead, found a great depth of water. Captain Clark, from Denia, in latitude 36° 24´ N., between nine and ten in the morning, had his ship shaken and strained as if she had struck upon a rock, so that the seams of the deck opened, and the compass was overturned in the binnacle. Another ship, forty leagues west of St. Vincent, experienced so violent a concussion, that the men were thrown a foot and a half perpendicularly up from the deck.” It is worthy of note that this, the most destructive Earthquake recorded in history, was not attended with any volcanic eruption; which goes to confirm our theory that the active Volcano serves as a kind of safety-valve for the escape of the struggling powers confined within the Crust of the Earth.[98] We must not bring our notice of Earthquakes to an end without at least some brief account of one which has startled the world even since we began to put together the materials of this Volume. On the Western Coast of South America there is a long, narrow strip of land, lying between the lofty crests of the Andes and the shores of the Pacific Ocean, which from the earliest times has been the familiar home of Earthquakes. Toward evening on the thirteenth of August, 1868, this fated region was the scene of a convulsion the most appalling and destructive that has been recorded within the present century. The disturbance was felt in its extreme violence for a distance of 1500 miles along the coast; from Ibarra one degree north of the Equator to Iquique more than twenty degrees south. In ten minutes from the first shock, 20,000 people perished, and a vast amount of property, roughly estimated at sixty millions sterling, was utterly destroyed. Many thriving towns--Iquique, Mexillones, Pisagua, Arica, Ylo, Chala, and others--were levelled to the ground. Even the very ruins were not spared. The sea rushed in when the Earthquake shock had ceased, and carried everything before it in one universal wreck: so that in some cases not a vestige remained behind to tell the dismayed survivors where their homesteads once had stood. It might be fancied perhaps that the cities seated aloft in the security of the Eternal Hills were beyond the reach of the convulsion that shook the plain below. But no: Arequipa, far up on the slopes of the western Cordillera, and Pasco, the highest city in the world, situated on a level with the snowy summit of the Jungfrau, were shattered into fragments with the same violence as the cities of the coast.