Page:Physical Geography of the Sea and its Meteorology.djvu/359

Rh 618. The work of re-adaptation, how carried on.—The waters of the Mississippi and the Amazon, together with all the streams and rivers of the world, both great and small, hold in solution large quantities of lime, soda, iron, and other matter. They discharge annually into the sea an amount of this soluble matter, which, if precipitated and collected into one solid mass, would no doubt surprise and astonish even the boldest speculator with its magnitude. This soluble matter cannot be evaporated. Once in the ocean, there it must remain; and as the rivers are continually pouring in fresh supplies of it, the sea, it has been argued, must continue to become more and more salt. Now the rivers convey to the sea this solid matter mixed with fresh water, which, being lighter than that of the ocean, remains for a considerable time at or near the surface. Here the microscopic organisms of the deep-sea lead are continually at work, secreting this same lime and soda, etc., and extracting from the sea water all this solid matter as fast as the rivers bring it down and empty it into the sea. Thus we haul up from the deep sea, specimens of dead animals, and recognize in them the remains of creatures which, though invisible to the naked eye, have nevertheless assigned to them a most important office in the physical economy of the universe, viz., [that of regulating the saltness of the sea (§ 489). This view suggests many contemplations. Among them, one, in which the ocean is presented as a vast chemical bath, in which the solid parts of the earth are washed, filtered, and precipitated again as solid matter, but in a new form, and with fresh properties. Doubtless it is only a readaptation—though it may be in an improved form—of old, and perhaps effete matter, to the uses and well-being of man. These are speculations merely; they may be fancies without foundation, but idle they are not, I am sure; for when we come to consider the agents by which the physical economy of this our earth is regulated, by which this or that result is brought about and accomplished in this beautiful system of terrestrial arrangements, we are utterly amazed at the offices which have been performed, the work which has been done, by the animalculae of the water. But whence come the little silicious and calcareous shells which Brooke's lead has brought up, in proof of its sounding, from the depth of over two miles? Did they live in the surface waters immediately above? or is their habitat in some remote part of the sea, whence, at their death,