machines."

"Two? Why is that?"

"Because we are going to travel through two, and perhaps three,
different mediums. We are going to shoot through the atmosphere
of the earth; then through the vast region beyond that, filled
with what is called ether."

"And is that different from our atmosphere?" asked Mark.

"Much different," replied Mr. Roumann. "There is no air to it at
all. The secret power which I have invented is perfectly adapted
to project us through this ether. That is why I call it
Etherium. Then when we reach Mars, we will find a different
atmosphere, somewhat like this earth's, I expect, but which will
require still another kind of power to move us in. I hope,
however, that the same force which sends us through the limits of
the atmosphere of this earth will take us through that of Mars.
So that is why I need so much space for machinery."

"Well, I guess we can build the projectile for you," said Mr.
Henderson. "It will take us nearly a month, though."

"No longer, I hope," said the German. "Every day is valuable.
Once the projectile is finished we will enter it, seal ourselves
up, and be shot through space. When we get to Mars--well, there
are many things to do when we reach there."

"I shall be much interested in seeing if they have discovered a