t is, half is
due to electricity and half is due to magnetism."

We are, however, only dealing at this point with the electro-static
energy in the electric field, as we shall deal with the electro-kinetic
energy in the following chapter.

We have, therefore, to conceive of an electrified body generating
electric or electro-magnetic waves, which speed away from the generating
source on every side with the velocity of light. Now we have already
seen that the aetherial waves which give rise to heat and light possess
a repulsive power, that is, they exert a pressure on the body with which
they come into contact.

If, therefore, in the electric field there is this energy manifested as
proved by Maxwell, and that energy takes partly the form of a pressure
as stated by Maxwell, then we have in the electro-static energy of the
electric field, another indication of that centrifugal force for which
we are looking, and whose existence was so satisfactorily demonstrated
to Herschel by the phenomena of comets' tails.

That there is this pressure in an electric field was conclusively proved
by Maxwell, and experimentally demonstrated by Professor Lebedew (Art.
77). Maxwell distinctly states on this point, "that the combined effect
of the electro-static and electro-kinetic stresses is a pressure equal
to 2 P. in the direction of the propagation of the waves," that is, away
from the electrified or charged body.

He continues: "Thus, if in strong sunlight the energy of light which
falls on one square foot is 83.4 foot-pounds per second, the mean energy
in one cubic foot of sunlight is about .0,000,000,882 of a foot-pound,
and the mean pressure on a square foot is .0,000,000,882 of a pound
weight. A flat body exposed to sunlight would experience this pressure
on its illuminated side only, and would therefore be _repelled_ from the
side on which the light falls."[31]

This pressure only gives the result due to the pressure of one cubic
foot of sunlight. What must be the pressure, therefore, due to the whole
of the sunlight received by the flat body from the sun? The total
pressure, whatever it may be, would be equal to 2 P. according to
Maxwell, and half of that is due to electricity, and half due to
magnetism. Now such a result is entirely in harmony with the conception
of the Aether as given in this work. For, if Aether possess an electric
basis as suggested by Maxwell, and it is also gravitative as suggested
in Art. 45, then it