=The Lag of Earth Temperatures.= The solar rays reach their greatest intensity on June 21st, in the Northern Hemisphere, when the sun attains the farthest point north, and the obliquity of its rays is the least, but the highest temperature of the air for the year does not occur on the average for a month or six weeks later, due to the capacity of the earth and air to absorb heat; and the maximum for the earth does not occur until still later. The sun is the farthest south on December 21st, but the minimum air temperature of the year, on the average, does not occur until a month later, and at a later period in the earth. At Munich, Bavaria, at a depth of four feet, the minimum annual temperature occurs on the 2d of March, and the maximum on the 24th of August. For each increase of four feet in depth the time of occurrence of either maximum or minimum temperature is retarded twenty-one days, the minimum not occurring until the 23d of May at a depth of 20.2°, and the maximum being retarded until the 17th of November. =Annual Range in Air Temperature.= The difference in temperature between winter and summer increases from the equator northward and from all oceans toward the interior of continents, and is greater in the middle latitudes on the eastern side of large bodies of land than on their western side. Yakutsk, Siberia, has experienced 80° below zero in January and 102° above in July, making a range of 182°. Dawson, Canada, has a record of 68° below for winter and 94° above for summer, making a range of 162°. In marked contrast with these large differences, shown in the northern interior of continents, is the annual range at Samoa, from a maximum of 92° to a minimum of 62°, a range for the year of only 30° for this island of the Pacific, located near the equator. =Reversal of the Seasons in the Two Hemispheres.= The summer is shorter in the Southern Hemisphere than in the Northern and the winter is longer, but the Southern Hemisphere is nearer to the sun in the summer and farther away in winter, conditions that tend to add to the extremes of both seasons. Because of the slowness of the earth in passing through one half of its orbit, the northern summer lasts ninety-three days, while that of the Southern Hemisphere lasts but eighty-nine days. The result is that during like seasons and during the whole year the two hemispheres receive exactly the same quantity of heat.