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17—3.
VARIOUS FORMS OF ELECTROSCOPES 391
fully
cleaned and evacuated,
then lled With gas. The leaf system
EL13 charged by the Wire W and draws ions—of opposite sign to the
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É
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collecting electrode E which results ina movement
proportional to the intensity of the emana'tion.
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,
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Neutrons eject protons from parain.___ The i0nîzafîon Of 3- gas
by the recoil protons can be
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measure
of the neutron
The
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neutron electroscopa3 of. guIÇ
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of a sensitive electroscope
chamber (Æ ; of, perhaps;J8‘eœnümefêïssx
A
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length and 5 centimeters diameter. The
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inner Walls of thecllamberare °°aæd
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with parain (B) apprommaœlyonemhï
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Aheavyshœld@f1ædsaYc17-8Ane““°“
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