Lieut. Maury, U. S. N., of the National Observatory at Washington, delivered a lecture at the Tabernacle, this city, en the 12th inst., being one ol the " Peoples' Course of Lectures." The above caption Was the title of the lecture. The audience was large, lor the fame of the lecturer is world-wide, his researches into the winds and currents of the sea have gained for him a great scientific reputation. Lieut. Maury was dressed in the naval uniform. He is about the medium size, firm, square, and compactly built, and like many men who have been greatly distinguished—he is lame—has a halt in his walk. He is of a fair and ruddy countenance and not over 45 years of age, we should conjecture. He has a broad open forehead, brown hair, fine manly face, and has a modesty of demeanor, no fustian rant nor cant about him. His voice is clear, but he is not an orator, although much oT his language is poetry, lofty and sublime. His lecture was divided into two distinct heads. He could not in one brief hour but touch on the salient angles of his subject.— j The one idea was, the sea being salt was the cause of currents, which, if it were fresh would not have an existence. The other was that marine animals and plants were the causes of currents in the sea. By the great evaporation in the equatorial regions cnly fresh water is lifted up, which leaves the salt water of the ocean denser than it was before, and the heavier particles rushing in to supply the place of the lighter is the cause of motion in the sea. The waters carried in clouds from the evaporating regions are condensed in other regions, especially the polar, and flow down in the rivers, to the northern ocean, and then the fresh water being lighter, flows on to the equator on the surface, while the denser salt water floats from the equator to the arctic ocean. Lieut, De Haven while on the Grinnell expedition, saw a huge iceberg floating away by an under current, while he was drifting in an opposite direction by a surface current. Owing to the sea being salt, we have those currents, which in the arrangement of Providence carry warm showers to fertilize regions, that otherwise would be inhospitable and barren. The waters which are carried into the sea, bear down limous matters ; these are taken up and secreted by coraline insects, which, as they build their marine palace walls, turn aside the billows from former courses, and direct the ways of the mighty waters. Lieut. Maury said that whenever he found in the Bible a foundation lor any theory, he was sure to go on in eliminating scientific truth. He paid it the humble but noble tribute of a great mind, as being the most scientific of all books, because it was the product of the Author ol all science.