If we now incline the axis of our imaginary earth 23½°, we shall introduce seasons whose only change, the one from the other, will be in the duration of sunlight, as there is no water vapor to absorb and utilize the sun’s rays in the initiation of motion and the creation of storms. We are assuming that there would be enough heat absorbed to prevent the atmosphere from liquefying, which it would do at any temperature lower than 312° below zero. If the temperature were to fall below the liquefying point of air, we would have the singular phenomenon of the air expanding to a gas during daylight and condensing to a liquid during nighttime, and, of course, that would mean motion and winds, but of such a nature that one would hardly dare speculate as to their peculiarities. We introduce these hypothetical cases for the purpose of conveying a clearer idea of the overlapping of conditions and the combinations of forces that influence and control the seasons, the climate, and the weather of the earth. If the surface of the earth were all water and its axis perpendicular to the plane of its orbit, the day and the night would everywhere be equal and there would be no seasons. With a water surface there would be an atmosphere nearly if not quite saturated with vapor of water, in other words, of practically one hundred per cent. relative humidity. It is doubtful if either animal or vegetable life could exist; the first would die of internal heat, because a saturated air would permit of no cooling by evaporation from the pores of the skin, or from the tongue and mouth of animals that do not perspire; and the second could not grow without the chemical action of sunshine, which is a necessary part of the laboratory of the leaf of every growing plant, the sunshine acting upon the green granular matter which constitutes the chlorophyll of the plant. There would be little difference between the temperature of day and of night—probably not more than one degree. As the earth would everywhere and at all times be covered with a deep stratum of cloud there would be little loss of heat to space by radiation and the temperature would be excessive, rising in the tropics to near the boiling point. We will assume that the atmosphere would reach a stable and unchanged condition of great heat and humidity and be without motion or precipitation.