Third, that of the isotherms of 50° for the warmest month, which are considered as the polar limits of the temperate zones, the one is much nearer to the north pole than the other is to the south. Great masses of water, we know, have a tendency to equalize climate, as the water heats and cools more slowly than the land; but they do not make the average temperature higher. From the movement of the waters of the ocean their temperature over the globe is more nearly equal, while the stable land of broad continental masses has temperatures more nearly corresponding to the latitude, though with greater daily and annual extremes. But for practical purposes, that is for its effect on vegetation, the amount of heat received in summer is of more consequence than the extreme cold of winter. For this reason the temperature of the warmest month instead of the annual mean is taken as the measure; for if that month’s mean temperature is below 50°, cereals and trees will not grow. The broad land masses in the Northern Hemisphere have a greater summer heat than the narrow stretch of land in extreme South America. The greater cold of winter in the north temperate zone does no harm. We may observe further that in the Northern Hemisphere the west coasts of both continents are warmer in the same latitude than the east, at least in the temperate zone, while in South America a good part of the west coast within the tropics is much cooler than the east. In the temperate zone the variation is slight. In the matter of rainfall, a most important factor of climate and production, South America is favored with a liberal supply, the arid portions being comparatively small in area, and many of these easily capable of irrigation and of resulting excellent crops. Dividing the continent into tropical and temperate regions, the former includes (lowlands only) the entire north coast, the whole of Colombia with ports on the Pacific, and Ecuador beyond, the low interiors of Peru and Bolivia, and around on the east the greater part of Brazil, far beyond the mouth of the Amazon; these sections have much in common as to climate and productions. Below Ecuador on the west coast, though still in the torrid zone, we find cooler weather, practically no rain, and for 1600 miles a desert region; beyond this there is a temperate climate with gradually increasing rainfall, and at last in southern Chile too much. On the east coast tropical weather and products continue till we pass Santos and the Tropic of Capricorn, followed by sub-tropical and temperate climates and production. The mountainous regions even at the equator have cooler weather, the temperature ever lowering with increase of altitude. OTHER DISTINCTIVE FEATURES