(6.) Chimneys of rock crossing the lower strata, as of quartz and granite, are now known to be of water deposit. The word dyke is improperly applied to them. These circumstances all point to a center of water. 4. The question with many will arise, How can rock rest upon water? The answer is, Upon the principle of the compressibility of liquids. Water compresses a twentieth part in a thousand atmospheres. Thirty-three feet of water is equal to one atmosphere. Thirty-three thousand feet would compress one-twentieth part. We have a geometrical series, with a ratio of 1.05. In 79-1/2 miles we have twelve and three-fourths terms. The sum of the series will equal 19.127, calling 33,000 feet _one_, without compressibility. Now as the average rock, under salt water, weighs only one and a half times as much as water, we have to multiply twelve and three-fourths by one and a half to get its relative weight. This we find to be 19.125. At 79-1/2 miles in salt water, the weight of water equals rock of the same thickness. As rock displaces only its bulk of water, it will swim like an egg in strong lye at this depth. 5. The explorations which have been made of the Atlantic ocean go to sustain the Neptunian theory. (1.) They think that they have established the fact that we had a connected land hemisphere, and a hemisphere of water. Lieutenant Maury made such extensive explorations of its contour and bed, as to well nigh demonstrate the above position. His report is, that the trough-like appearance of its bed, the corresponding walls on either side, being nearly perpendicular, showed that the continents were once together. On either side of the Atlantic the sounding line showed a gradual deepening of water for about two hundred miles from shore, when suddenly the depth became too great for measurement. This only confirms what Guizot wrote upon the same subject over fifty years ago. In a small treatise he endeavored to prove that the continent showed a rent hemisphere of land, once altogether. That it had been rent asunder by some great convulsion of nature, and by water carried away from Africa and Europe, with which North and South America were formerly connected. His theory was, that continents and islands are but floating remnants of a once connected hemisphere. (2.) Such a rupture could only be maintained on the hypothesis of a center of water. Should the earth open its crust, letting the ocean into its interior of melted lava, it would resemble a bomb. 6. We shall, therefore, assume that we had a land hemisphere, and that the north pole was in the center, and pointed directly to the sun throughout its entire orbit. This would involve the fact that the south half of the globe was in darkness, and locked in ice, as a great Antarctic sea.