INTRODUCTION TO TEMPERATURE OF THE OCEAN Although water, of all substances, has the greatest capacity for heat—or, in other words, has the highest specific heat—yet it is a bad conductor of heat. Thus heat applied to one part of a mass of water, is not transferred from atom to atom, as when applied to a piece of iron or other metal; but the particles of water first heated change their position, and are replaced by other particles, which are heated and displaced in turn, and so on until the whole mass is uniformly heated. Water is thus heated—or, in other words, the temperature of water is raised—by an actual transfer of all its particles suc cessively to and from the source of heat. It will be thus seen that the greater amount of heat required to raise the tem perature of water, and the distribution of that heat by con vection only, makes the heating of large masses of water a very slow process. Compared with the land, water requires four times as much heat to raise it to the same temperature. The
sea, therefore, is not so readily heated as the land ; nor, on the other hand, does it cool so quickly when once heated. Con sequently, the sea is, on the whole, more equable as regards temperature than the land—that is, the difference between the temperature of the sea during the day and at night, or in summer and winter, is not so great as that of the land. In summer the land has a generally higher tem perature than the adjacent sea ; but in winter the sea is, on the whole, warmer than the land. The sea is thus a great " storehouse of heat," cooling the land in summer by abstract ing and storing the very heat which is given out to warm the land in winter. This equability, or comparative invariability of the temperature of the sea, has a most beneficent influence on the climate especially of maritime countries, Which are nowhere subject to the great extremes of heat and cold that characterize the climates of inland countries.