Page:Popular Science Monthly Volume 61.djvu/11

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THE

POPULAR SCIENCE

MONTHLY



MAY 1902.



THE ELECTRONIC THEORY OF ELECTRICITY.
By Dr. J. A. FLEMING, F. R. S.,
PROFESSOR OF ELECTRICAL ENGINEERING, UNIVERSITY COLLEGE, LONDON.

CONSIDERABLE progress has been made of late years in our knowledge concerning the structure and relations of atoms and electricity. Recent discoveries have moreover placed in a new light old theories and experimental work. The remarkable investigations and deductions made from his own experiments and those of others, which have led Professor J. J. Thomson to the conclusion that atoms can be split up into, or can give off, smaller masses, which he calls corpuscles, were explained by him in a most interesting article in the Popular Science Monthly for August, 1901.[1] There seems to be good evidence that in a glass vessel exhausted to a high vacuum through the walls of which are sealed platinum wires, we have a torrent of small bodies or so-called corpuscles projected from the kathode or negative wire, when the terminals are connected to an induction coil or electrical machine.

Twenty-five years ago Sir William Crookes explored with wonderful skill many of the effects due to electric discharge through such high vacua, and came to the conclusion that they could only be explained by the supposition that there was present in the tube matter in a fourth state, neither solid, liquid, nor gaseous, but 'radiant matter 7 projected in straight lines from the surface of the negative pole or kathode, the particles moving with immense velocity, and all charged

  1. See Popular Science Monthly, Vol. LIX., p. 323, 'On Bodies Smaller than Atoms,' by Professor J. J. Thomson, F.R.S. See also by the same author a paper in the Philosophical Magazine for December, 1899, 'On the Masses of the Ions in Gases at Low Pressures.'