Lessons in the New Geography

Ocean, Atmosphere, and Life. ? Elisee Reclus. LESSON I. ?THE ELEMENTS OF CLIMATE. Definition. ? Climate is the character of the atmosphere dependent upon the condition of two primary factors, temperature and moisture. The condition of these two main elements is influenced by : i, latitude or distance from the equator; 2, altitude or height above the sea level; 3, distance from the sea; and 4, prevailing winds and ocean currents. From all of these causes arises that diversity of climate which is so marked a feature of the earth's surface. We speak accordingly of a hot or a cold, or of a dry or a moist climate. The word ' climate' is of ancient origin. It comes from a Greek verb meaning to incline, and was used by the ancients to signify the difference in the length of day and night, resulting from the slanting or inclination of the sun's rays in relation to the time and place. This fact was recognized by the ancient geographer Ptolemy (127-151 A.d.), who divided the earth's surface, from the equator to the arctic circle, " into climates or parallel zones, corresponding to the successive increase of a quarter of an hour in the length of midsummer day." Latitude or Distance from the Equator. ? On those parts of the earth where the sun's rays fall more or less directly downward, the temperature of the air is raised. This is the case, Fig. 1. ? Diagram illustrating the result of vertical and slanting rays of sunlight on the earth's ...