CHAPTER 1
THE CHARGE OF THE ELECTRON
1—1.
Introduction.—The granular structure of electricity has
been observed in widely different elds of physics by many different methods.
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For example, the individual charges emitted by the
hot lament in a radio tube are always of a denite, small amount,
regardless of the material or the temperature of the lamer‘1t. The
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particles spontaneously emitted by radioactive substances carry
either one or tWo times this small amount.
Again, the electried
particles in the air around us carry an integral multiple of this
natural unit of electrical charge. Further, the frictional electricity
on drops of water or oil sprayed from an atomi2er is found to have
this same granular structure.
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.
The name electron was rst applied to the smallest amount
of electricity found in nature, in 1874 by C. ]. Stoney. Since then
additional properties have been associated with this charge, such
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as mass and wave-length, so that it has become an entity in itself
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instead of a unit of electricity.
,
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It is a common constituent of all
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atoms.
Extensive studies have been made of the energy required
to shift electrons from their normal condition and even to remove
them from theatomsof various elements.
ræearCh, new
laWs
properties of Nature have been discovered.
‘
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electrons which carry a negative charge -are by
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‘inost
and
and”will be referred to throughout
as electrons.
The rarer, positively chargedelec—
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