Introduction

Abstract

At six o’clock on the morning of August 7, 1912, the Austrian physicist Victor Hess and two companions climbed into a balloon gondola for the last of a series of seven launches. The flight, which had started at Aussig on the river Elbe, was under the command of Captain W. Hoffory. The meteorological observer was W. Wolf and Hess listed himself as “observer for atmospheric electricity”. Over the next three or four hours the balloon rose to an altitude above 5 km, and by noon the group was landing at Pieskow, some 50 km from Berlin. During the six hours of flight Hess had carefully recorded the readings of three electroscopes he used to measure the intensity of radiation and had noted a rise in the radiation level as the balloon rose in altitude.