the sense of using the last reserves, but, on the contrary, the human organism seems to react to this loading with a certain increase in resistance to altitude.
In descending experiments from 13 km. [42,700 ft.] altitude the waiting time of 10 seconds was retained, but on the other hand exertion in the form of knee bends was omitted since technical difficulties interfered with this procedure.
The experiments involving suspension could be done only in the large low-pressure chamber, since suspension was impossible in the small low-pressure chamber for reasons of space. Therefore, the ascent to 13 km. [42,700 ft.] altitude was carried out slowly in the main chamber (without explosive decompression) so that when 13 km. [42,700 ft.] was reached a certain oxygen lack existed. With this oxygen lack the knee bends would have presented a great burden which would have falsified too greatly the results of the experiment. The same conditions were also given in further experiments at higher altitudes in the main chamber. For this reason, the 13 km. [42,700 ft.] descending experiments were carried out partly in the sitting position, partly in the sitting position strapped in, and partly suspended. They yielded the following average data:
Descending experiment │ Unconsciousness │Recovery of consciousness from 13 km. [42,700 ft.] │ after— │ after— │ │ Seated (lying during │50″ = 12.4 km. │8′ 12″ = 7.2 km. unconsciousness) │ │ │ [40,672 ft.]. │ [23,620 ft.]. Seated strapped in │35″ = 12.6 km. │10′ 30″ = 5.85 km. │ [41,340 ft.]. │ [19,190 ft.]. Suspended │20″ = 12.8 km. │19′ = 1.6 km. │ [41,980 ft.]. │ [5,250 ft.].
Since in unfavorable cases in these experiments, namely while suspended, recovery of consciousness did not occur until 1.6 km. [5,250 ft.] altitude, it had to be concluded that in jumps from altitudes over 13 km. [42,700 ft.], recovery of consciousness would follow only after 0 km., which would mean that in an actual situation the landing would be made in an unconscious condition. This raised the question of a safe means of rescue.
Descending experiments were made in larger numbers from 15 km. altitude, since it became evident that at this altitude the approximate limits for what was possible in emergencies had already been reached or essentially surpassed. After an ascent made as rapidly as possible, using oxygen apparatus with free flow, the mask was removed immediately upon attaining 15 km. [49,200 ft.] altitude and the descent was begun. Since the results of these descending experiments were very typical and especially impressive it is necessary to present one of these experiments in detail. The record of an experiment is represented as follows: