The ocean teems with life, we know. Of the four elements of the old philosophers,--fire, earth, air, and water,--perhaps the sea most of all abounds with living creatures. The space occupied on the surface of our planet by the different families of animals and their remains is inversely as the size of the individual; the smaller the animal, generally speaking, the greater the space occupied by his remains. Take the elephant and his remains, and a microscopic animal and his, and compare them; the contrast as to space occupied is as striking as that of the coral reef or island with the dimensions of the whale. The graveyard that would hold the corallines, is larger than the graveyard that would hold the elephants. DEPTHS OF OCEAN AND AIR UNKNOWN. At some few places under the tropics, no bottom has been found with soundings of 26,000 feet, or more than four miles; whilst in the air, if, according to Wollaston, we may assume that it has a limit from which waves of sound may be reverberated, the phenomenon of twilight would incline us to assume a height at least nine times as great. The aerial ocean rests partly on the solid earth, whose mountain-chains and elevated plateaus rise like green wooded shoals, and partly on the sea, whose surface forms a moving base, on which rest the lower, denser, and more saturated strata of air.--_Humboldt’s Cosmos_, vol. i. The old Alexandrian mathematicians, on the testimony of Plutarch, believed the depth of the sea to depend on the height of the mountains. Mr. W. Darling has propounded to the British Association the theory, that as the sea covers three times the area of the land, so it is reasonable to suppose that the depth of the ocean, and that for a large portion, is three times as great as the height of the highest mountain. Recent soundings show depths in the sea much greater than any elevations on the surface of the earth; for a line has been veered to the extent of seven miles.--_Dr. Scoresby._ GREATEST ASCERTAINED DEPTH OF THE SEA.