Abstract
A MORE complete account of the scientific results achieved in the stratosphere flight of November 11, 1935, has now been published in the May number of the National Geographic Magazine. The tube counter directional system for cosmic rays was described in NATURE of June 29, 1935, p. 1083, and it would now appear that some modification must be made in the results from Explorer I. At an altitude of 72,000 feet covering 96 per cent of the earth's atmosphere, the rays show no directional preponderance from the vertical to the horizontal. It follows that as those rays coming from the more horizontal directions increase with height, these are influenced by the earth's magnetic field. Swarm's explanation of the distribution is that most, if not all, the rays observed are secondaries. The Stoss chamber for observing bursts did not show any abnormal increase in their number with height. The following numbers are given for cosmic ray activity: at 40,000 ft., 40-1 times that at sea-level (Explorer I on July 28, 1934, gave this number as 42-3); at 53,000 ft., 51-5 (Piccard in autumn of 1934 gave 53-2); at 57,000 ft., 55, a maximum, and at 72,395 ft., 42. A Wilson chamber was not taken up, but the next best method, of recording in the body of the photographic emulsion of a plate, gave a track of an a-ray of energy 108 electron volts. The ion content of the air roughly follows the cosmic ray activity at great heights. Previous records only went up to 30,000 ft. In these experiments, the maximum was observed at 61,000 ft. of 81 times that at sea-level, and at the greatest height of 72,000 ft. this figure fell to 50. There may be some connexion between this and the observed decrease in the strength of radio signals received on the ground from above a height of 60,000 ft. Other results quoted are that 20 per cent of the ozone content of the atmosphere lies below 72,000 ft., the composition of stratosphere air is insignificantly different from that at sea-level and above 60,000 ft. only moderate wind velocities ranging up to 42 miles per hour are met with. From the temperature-altitude chart given, it appears that the temperature ranged round about –70 ° F. from 35,000 ft. to the maximum heights from 9.40 a.m. to 2 p.m.
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U.S. Stratosphere Balloon Explorer II. Nature 137, 896–897 (1936). https://doi.org/10.1038/137896c0
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DOI: https://doi.org/10.1038/137896c0