ssage through the earth's atmosphere.

Of the light itself Professor Newland had already given his opinion. It
was, he said, some unknown form of etheric vibration. It radiated heat
very slightly, but it had the peculiarity of generating intense heat in
anything it touched directly.

"You'd better explain that, father," said Beth, when we reached this point
in our summary that evening.

"Heat is the vibration of molecules of matter," the professor began.

I nodded.

"Make it clear when you write it up, Bob," Alan put in. "It's like this.
All molecules are in motion--the faster the motion, the hotter the
substance, and vice versa."

"And this Mercutian Light," Beth added, "has the power of enormously
increasing the molecular vibration of anything it comes in contact with--"

"But it doesn't radiate much heat itself," Alan finished.

Professor Newland smiled. "The old man doesn't have much of a show, does
he?"

Alan sat down somewhat abashed, but Beth remained standing beside her
father, listening intently to everything he said.

"This light I conceive to be the chief weapon of warfare of the
Mercutians," the professor went on. "There has been some talk of those two
meteors being signals. That's all nonsense. They were not signals--they
were missiles. It was an act of aggression."

I tried to get him to give some idea of what the inhabitants of Mercury
might be like, for that was what my editor chiefly desired.

At first he would say nothing along those lines.

"That is pure speculation," he explained. "And very easy speculation, too.
Any one can allow his imagination to run wild and picture strange beings
of another world. I don't predict they will actually land on the
earth--and I have no idea what they will look like if they do land. As a
matter of fact, they will probably look very much like ourselves. I see no
reason to doubt it."

"Like us?" I ejaculated.

"Why not?" said Alan. "Conditions on Mercury are not fundamentally
different from here. We don't have to conceive any very extraordinary sort
of being to fill them."

"Here's what you can tell your paper," said the professor abruptly. "Take
it down."

I took out my notebook, and he dictated briskly.

"Regarding the possible characteristics of inhabitants of Mercury, it is
my conception that intelligent life--let us say, human life--wherever it
exists in our universe does not greatly differ in character from that of
our own planet. Mars, Venu