1370. Inconsiderable seas, in temperate and cold climates, are colder in winter and warmer in summer than the main ocean, as they are necessarily under the influence of natural operations from the land. Thus, the Gulf of Bothnia is generally frozen in winter, but the water is sometimes heated in the summer to seventy degrees, a state which the opposite part of the Atlantic never acquires; the German Sea is five degrees warmer in summer than the Atlantic, and more than three colder in winter; the Mediterranean is almost throughout warmer both in winter and summer, which therefore causes the Atlantic to flow into it; and the Black Sea, being colder than the Mediterranean, flows into the latter.
