dilution the repelled polar particles will be able to traverse the space
open to them without any essential alteration in their speed, the small
number of the existing gaseous molecules being no longer able to retard
the molecules of the polar no their journey through the apparatus. The
luminous phenomena of the Geissler tubes the author supposes to be
produced by the intense blows which the gaseous molecules receive from
the polar molecules flying rapidly through the apparatus. The intensity
of the luminous phenomena will naturally decrease with the number of
the photophorous particles occupying the space. Accordingly in the
experiments of Crookes, on continued rarefaction of the gas, a condition
was reached where a display of light is no longer perceptible, or can be
made visible merely by the aid of fluorescent bodies. A condition may
also appear, as is shown by Crookes' experiment, with the metallic plate
intercalated as negative pole in the middle of. a Geissler tube, with
the positive poles at the ends. In this case the gaseous molecules are,
so to speak, driven away by the polar particles endowed with an equal
initial velocity, till at a certain distance from the pole the mass of
the gaseous molecules and their speed become so great that a luminous
display begins. In an analogous manner the author explains the phenomena
of phosphorescence which Crookes' elicits by the action of his radiant
matter. In like manner the thermic and the mechanical effects are most
simply explained, according to the expression selected by Crookes
himself, as the results of a "continued molecular bombardment." The
attraction of the so called radiant matter, regarded as a stream of
metallic particles by the magnet, will not appear surprising.

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