Thus arises the first great contrast which we have to study: the first, and next to the great primary distinction between the North and South, the most important. The division into land and water, aside from commerce, must exercise the strongest influence on the distribution of heat and cold, affecting the temperature of all the zones. This influence has been fully noticed and brought before the world by Alexander von Humboldt. It is sufficient to refer to it now as a well-determined fact in physical geography. The heat equator is a little farther north than the mathematical equator, because the land hemisphere has a greater heat capacity (if we may use an awkward but apt word) than the water hemisphere. All other isothermal lines are modified in their greater or less coincidence with the parallels of latitude as they advance from the heat equator toward the maximum of the land hemisphere, or, in general terms, as they go northward. In the western hemisphere the isothermal lines follow much more exactly the parallels of latitude than in the eastern, which is pre-eminently the land hemisphere. In America the proximity of immense masses of water causes a perceptible reduction of the heat from that of the eastern where the land form prevails. And the heat diminishes more as we advance toward the South Pole, than toward the North, in consequence of the greater deficiency of land in the southern hemisphere; while in Lapland, Greenland, and in Siberia, even within the polar circle itself, men find sustenance and trees live, in the same latitude, at the South Pole, no vegetable life, worth mentioning, is found. The frigid zone and the temperate zone of the southern hemisphere are not coincident with those of the northern. The icebergs which are formed at the South Pole are carried much nearer to the equator than those found at the North Pole. An important phenomenon, first pointed out by A. von Humboldt and Dove, is closely connected with what has just been said. The Atlantic shores of the old world are warmer than those in the same latitude of the new world. Norway, England, and France are warmer than Labrador and Canada; Spain, Portugal, and Morocco are warmer than Florida; Congo and Benguela are warmer than Brazil, although the countries brought in contrast all lie on the same parallel. A similar analogy is drawn from the west shore of America: Northern California is warmer than Japan and Corea, which are in the same latitude. It is true, other factors are at work to produce this, such as winds, marine currents, elevations of land, etc., of which more will be said hereafter.