times a second, and
the sound travels 1100 feet in the same interval, the length of each
wave will be found by dividing the velocity in the air by the number of
vibrations, or 1100 / 500 = 2.2 feet. In like manner, when one knows
the velocity and wave-length, he may compute the number of vibrations by
dividing the velocity by the wave-length. Now the velocity of the waves
called light is 186,000 miles a second, and a light-wave may be one
forty thousandth of an inch long. The atom that produces the wave must
be vibrating as many times per second as the fifth thousandth of an inch
is contained in 186,000 miles. Reducing this number to inches we have

186,000 x 5280 x 12
------------------- = 400,000,000,000,000, nearly.
1/40,000

This shows that the atoms are minute elastic bodies that change their
form rapidly when struck. As rapid as the change is, yet the rate of
movement is only one-fifth that of a comet when near the sun, and is
therefore easily comparable with other velocities observed in masses of
matter.

These vibratory motions, due to the elasticity of the atoms, is what
constitutes heat.

THE ETHER IS ELASTIC.

The elasticity of a mass of matter is its ability to recover its
original form after that form has been distorted. There is implied that
a stress changes its shape and dimensions, which in turn implies a
limited mass and relative change of position of parts and some degree
of discontinuity. From what has been said of the ether as being
unlimited, continuous, and not made of atoms or molecules, it will be
seen how difficult, if not impossible, it is to conceive how such a
property as elasticity, as manifested in matter, can be attributed to
the ether, which is incapable of deformation, either in structure or
form, the latter being infinitely extended in every direction and
therefore formless. Nevertheless, certain forms of motion, such as
light-waves, move in it with definite velocity, quite independent of how
they originate. This velocity of 186,000 miles a second so much exceeds
any movement of a mass of matter that the motions can hardly be
compared. Thus if 400 miles per second be the swiftest speed of any mass
of matter known--that of a comet near the sun--the ether-wave moves
186,000 / 400 = 465 times faster than such comet, and 900,000 times
faster than sound travels in air. It is clear that if this rate of
motion depends upon elasticity, the elasticity must be of an entirely
diffe