=Temperatures Aloft in the Atmosphere.= Kite and balloon observations have not been continued long enough, nor have they been made at a sufficient number of places, to give one the data from which the climate of any considerable altitude in the free air may be determined, but from a large number of free balloon observations made with self-recording instruments, in the middle latitudes of this and foreign countries, Figure 1 (page 12) has been constructed, which shows the manner in which the temperature decreases with elevation up to eighteen kilometers (eleven miles). Note how rapidly it falls with elevation up to eleven and a half kilometers (about seven miles). This depth of air measures the thickness of the turbulent stratum in which cyclones and anti-cyclones operate. At its top the temperature always is about 64° below zero in winter and 70° below in summer. And right here occurs a most wonderful phenomenon,—one of which scientists were entirely ignorant less than two decades ago. At first it was thought that there was something wrong with the recording thermometers, for they failed to register falling temperature with gaining altitude after the storm stratum was passed at seven miles. Then it was noted that all instruments displayed the same peculiarity, and the “Isothermal Stratum” (equally heated region) was discovered, in which the temperature maintains the same degree of intense cold so far as exploration had been made. From Mount Weather, under the direction of the writer, a balloon was flown to nineteen and one tenth miles before it exploded and sent a parachute gently down to earth with its precious record. This flight showed practically no change in temperature after the isothermal stratum was reached. (See Chapter III.) One is reasonably safe in assuming that there is no oxygen beyond an altitude of thirty miles and that at fifty miles the nitrogen becomes inappreciable, and that, therefore, the temperature must shade away to practically nothing when the void of outer space is reached, notwithstanding the presence of the newly-discovered isothermal stratum nearer the earth. CHAPTER XII CIVILIZATION FOLLOWS THE STORM TRACKS THE MOST DOMINANT RACES—THOSE THAT BEST CO-ORDINATE THE MENTAL AND PHYSICAL FACULTIES—ARE FOUND TO EXIST UNDER CERTAIN CLIMATIC CONDITIONS—CHANGE THE CLIMATE AND YOU CHANGE THE MAN