The reorganization of balloon observations was accomplished by the German Society for the Promotion of AÎrial Navigation, which has been assisted by the Prussian Meteorological Institute, and by officers of the German Army Balloon Corps. The German Emperor takes a personal interest in the work, and has aided it by the gift of a considerable sum of money. The first voyage under the direction of the Society was made in 1888, and many notable ones followed. In 1891, through the courtesy of the president, Dr. Assmann, the writer made an ascent from Berlin in a balloon equipped for accurate observations, with the special purpose of comparing the sling with the aspiration thermometer. The car of the balloon is shown in Fig. 3. A companion was the now famous Dr. Berson, who then made his second ascent, but who has now become an expert aeronaut by reason of more than fifty ascensions, some of them to great heights. On December 4, 1894, he ascended alone from Stassfurt, Prussia, in the _Phoenix_, to probably the greatest height ever reached by man, at least in a conscious state. By breathing oxygen he was able to keep his senses and to read the barometer at 9∑1 inches, indicating approximately an altitude of 30,000 feet, and the aspirated thermometer at 54∞ below zero. An ordinary thermometer read 11∞ below zero in the sun, showing its heat was much diminished in consequence of the haze that prevailed even at this enormous height. The cirriform clouds which surrounded the balloon were found to have the structure of snow-flakes rather than that of ice-crystals. The chief result of this record-breaking ascent was the extraordinarily low temperatures recorded at great heights, as compared with those observed by Glaisher, Tissandier, and others. An inversion of temperature--that is an increase of temperature with height--prevailed up to a mile, but above that the temperature fell at a rapid and accelerated rate which approached the adiabatic fall above 26,000 feet. The wind, which was almost calm at the earth's surface, increased to a gale in the high atmosphere, and carried the balloon along at an average speed of thirty-six miles an hour. Wishing to demonstrate conclusively whether the insular position of England influenced the temperature of the high atmosphere, as had been suggested, Dr. Berson determined to execute a high ascension in England during the prevalence of a barometric maximum in summer, when the air column would be abnormally warmed and the upper isothermal surfaces elevated. An opportunity was afforded Berson to follow in Glaisher's footsteps on September 14, 1898, when abnormal heat prevailed in Europe. Berson, with the aeronaut Spencer, in the balloon _Excelsior_, rose from the Crystal Palace in London to the height of 27,300 feet, where he observed a temperature of -29∞. The oxygen inhaled prevented harmful physiological effects except for the discomfort caused by the enormous reduction of temperature from 80∞ at