What a Teacher Should Teach


Let us suppose that a certain wise teacher of physics places a
row of Bunsen burners under a long steel bar having a Daniell's
pyrometer at one end, and addresses his class (substantially) as
follows:

"At our last lecture we found that the matter of the universe
permeated all space, but in two conditions, which we agreed to
call physical and etheric, or tangible and intangible. It is all
the same matter, subject to the same laws, but differing in the
rate of vibration, the physical matter vibrating through one
great octave or plane, and the etheric vibrating through another
great octave or plane one degree higher--the chording vibration
of the matter of the two planes in one note producing what we
call energy or force, and with it phenomena.

"This is a bar of steel 36 inches long. It is composed of
physical atoms but no two physical atoms touch. Each physical
atom is as far apart from every other atom as the stars in heaven
from one another--in proportion to their size. The atoms and
the spaces between them are so small to our sight that they seem
to touch. If we had a microscope of sufficient power to reveal
the atom, you would see that no two atoms touch, and that the
spaces between them are, as Faraday says, very great in
proportion to their size. I showed you last term that what
appeared to be a solid stream of water, when magnified and thrown
upon a screen, was merely a succession of independent drops that