RESULTS OF THE SALTNESS OF THE SEA It is a well-known fact that, under similar conditions, evaporation is much more rapid from fresh than from salt water. The actual difference has been experimentally proved to be about 0.54 per cent, so that it is highly probable that the saltness of the sea was " mainly intended to regulate evaporation." This "regulation of evaporation" is a most comprehensive term, and one that affects the physical "life of the globe" in almost every direction. The amount of moisture in the air, and therefore the rainfall, the water-supply, and dependent vegetable and animal life—in fact, almost all climatical phenomena, are either directly or indirectly affected by evaporation. As we shall again point out, the grand system of oceanic circulation is, most probably, primarily due to differences of density, consequent on excessive evaporation in certain localities. Had the sea, therefore, been fresh, evaporation would be much more active ; the rainfall would consequently be greater—countries now moderately moist would be almost constantly deluged with heavy rains and copious dews—in fact, the whole climatic conditional of every part of the earth would be changed, beneficially perhaps to some districts, but undoubtedly deleterious to the greater part of the civilized world.
But, besides being less vaporizable, salt water does not freeze so readily as fresh water. Fresh water freezes at 32° F., while salt water is not converted into ice until its temperature is reduced to 28i° F., or even lower. The result of this im portant difference is twofold—a larger portion of the sea is permanently open and accessible; and, bulk for bulk, the sea "stores," as it were, a greater degree of heat than the land —to be given out again when the latter is covered with the snows and ice of winter. By its capability of retaining per manently a greater degree of heat than the land, without a correspondingly high elevation of temperature, it moderates the heat of summer ; and, by its insensitiveness, if we may say so, to cold, it parts with its surplus heat to the land in winter without its temperature being reduced in the same degree. Both these results, less evaporation and slower con gelation, are undoubtedly due to the presence of the saline matters in solution in the waters of the ocean.