Production of the Joshi effect under β- and γ-rays

Examination of the literature having shown absence of information on the Joshi effect under radioactive emanations, a detailed investigation was made employing, in the first instance, a &#946;-ray capsule with negligible &#947; -ray activity. Siemens ozonizer type tubes charged with various vapours and gases and excited by commercial-frequency potentials of kilovolts were used. In agreement with results obtained with visible and ultra-violet radiation and with x-rays, and employing especially organic vapours, an exposure to &#946;-rays caused an instantaneous and reversible positive effect + &#916;i at relatively low voltage; with slight increase of voltage, + &#916;i diminished sharply; and finally changed over to - &#916;i above V<SUB>m</SUB>, the threshold for a 'self-maintained' discharge. Thus, for example, cyclohexane vapour showed under &#946;-rays about 150 per cent positive Joshi effect at 4 kV.; + 9.5 per cent and - 5.8 per cent at 6 and 8 kV respectively