a of the board. If
the wood be sound the board will support a thousand pounds readily.
Now remove the lead slabs and fire a 200 grain lead bullet at the
board with a muzzle or initial velocity of 1,600 feet per second. The
bullet will penetrate the board very readily. Consider the heaviside
layer as the board, the space ship as the lead slabs and the bullet as
the meteor and you have the answer.

Consider one more thing. According to the stories, the layer grew
thicker and harder to penetrate as the flyer reached the outer
surface. The meteor would strike the most viscous part of the layer
with its maximum energy. As its velocity dropped and its kinetic
energy grew less, it would meet material easier to penetrate. On the
other hand the flyer, coming from the earth, would meet material easy
to penetrate and gradually lose its velocity and consequently its
kinetic energy. When it reached the very viscous portion of the layer,
it would have almost no energy left with which to force its way
through. Remember, the Mercurians made no attempt to penetrate the
layer until a portion of it had been destroyed by Carpenter's genius.

As for the matter of refraction. If you will place a glass cube or
other form in the air, you will have no difficulty in measuring the
refraction of the light passing through it. If, however, the observer
would place himself inside a hollow sphere of glass so perfectly
transparent as to be invisible, would not the refraction he would
observe be taken by him to be the refraction of air when in reality it
would be the combined refraction of the glass sphere and the air
around him?

I have taken glass as the medium to illustrate this because my critic
made the statement that "a substance denser than air would produce
refraction that would have been noticed long ago." However nowhere in
either story is the statement made that the material of the heaviside
layer was denser than air. The statement was that it was more viscous.
Viscosity is not necessarily a function of density. A heavy oil such
as you use in the winter to lubricate your automobile has a much
higher viscosity than water, yet it will float on water, i. e. it is
less dense. There is nothing in the story that would prevent the
heaviside layer from having a coefficient of refraction identical with
that of air.

To close, let me repeat that I am not arguing that such a layer
exists. I do not believe that it does and I do believe that my
gene