nstance, does not seem to
raise the temperature of the ground it strikes to any extent?"

"Because, like electricity, it is dissipated the instant it strikes the
ground. The earth is an inexhaustible storehouse and receptacle for such a
force. That is why the broken country around the Shoshone River protected
Garland and Mantua from its direct rays."

"Tell me about the details of this mechanism," I said, reverting to our
original subject. "You say you understand its workings pretty thoroughly
now."

"Yes, I do," he admitted, "and so does father. But I cannot go into it now
with you. You see," he added hastily, as though he feared to hurt my
feelings, "the scientific men of Mercury--some of them--objected to
Miela's coming, on the ground that the inhabitants of the earth, obtaining
from her a knowledge that would enable them to voyage through space, might
take advantage of that knowledge to undertake an invasion of Mercury.

"As a matter of fact, that was a remote possibility. I could explain to
you all I know about this mechanism without much danger of your ever being
able to build such a car. But Miela promised them that she would use all
possible precautions, in the event of her having any choice in the matter,
to prevent the earth people learning anything about it.

"Father and I have examined everything here closely. But no one else
has--and I am sure Miela would prefer no one else did. You understand,
Bob?"

I did understand; and of course I had to be satisfied with that.

"It seems to me," I said when, later in the day, we were discussing
affairs in Wyoming, "that with things in Mercury as we now know they are,
it would help the situation tremendously if Tao and these Twilight People
with him were prevented from ever returning."

"That's my idea exactly," Professor Newland agreed.

I could see by the look on his face he was holding on to this thought as a
possibility that might make Alan's plan unnecessary.

"I've thought about it constantly," the professor said, "ever since these
facts first came to us through Miela. It would be important. With his
expedition here a total failure, I think we might assume that nothing more
would be done up there in attempting to conquer the earth. I've tried to
make Alan see that we should give the authorities all the information we
have. It might help--something might be accomplished--"

"Nothing would, father," Alan interrupted. "There wouldn't be time. And
even if