the ether the length of
the year would have been changed, and astronomers would have discovered
it. They assert that a change in the length of a year by so much as the
hundredth part of a second has not happened during the past thousand
years. This then is testimony, that a velocity of nineteen miles a
second for a thousand years has produced no effect upon the earth's
motion that is noticeable. Nineteen miles a second is not a very swift
astronomical motion, for comets have been known to have a velocity of
400 miles a second when in the neighbourhood of the sun, and yet they
have not seemed to suffer any retardation, for their orbits have not
been shortened. Some years ago a comet was noticed to have its periodic
time shortened an hour or two, and the explanation offered at first was
that the shortening was due to friction in the ether although no other
comet was thus affected. The idea was soon abandoned, and to-day there
is no astronomical evidence that bodies having translatory motion in the
ether meet with any frictional resistance whatever. If a stone could be
thrown in interstellar space with a velocity of fifty feet a second it
would continue to move in a straight line with the same speed for any
assignable time.

As has been said, light moves with the velocity of 186,000 miles per
second, and it may pursue its course for tens of thousands of years.
There is no evidence that it ever loses either its wave-length or
energy. It is not transformed as friction would transform it, else there
would be some distance at which light of given wave-length and amplitude
would be quite extinguished. The light from distant stars would be
different in character from that coming from nearer stars. Furthermore,
as the whole solar system is drifting in space some 500,000,000 of miles
in a year, new stars would be coming into view in that direction, and
faint stars would be dropping out of sight in the opposite direction--a
phenomenon which has not been observed. Altogether the testimony seems
conclusive that the ether is a frictionless medium, and does not
transform mechanical motion into heat.

8. MATTER IS AEOLOTROPIC.

That is, its properties are not alike in all directions. Chemical
phenomena, crystallization, magnetic and electrical phenomena show each
in their way that the properties of atoms are not alike on opposite
faces. Atoms combine to form molecules, and molecules arrange themselves
in certain definite geometric