Synopsis Europe, the smallest of the continents, is, taken as a whole, the most densely peopled. Its situation and outline are peculiarly favorable to its climate. The whole, area, except a small fraction in the north, lies within the temperate zone, and the great irregularity of its outline causes it to enjoy in a higher degree than any other continent the mitigation effects of the sea on extremes of heat and cold. Its westerly situation is of even greater importance in this respect, and its southern peninsulas have a peculiarly warm and equable climate, not only in consequence of the moderating effect of the Mediterranean Sea on the temperature, but also because these peninsulas are to a large extent protected from cold northerly winds by mountain-barriers on the north.