the planet; then looked up with an apologetic grin.

"I had a foolish idea. I thought--" He checked himself. "Say, doesn't
Venus remind you of something?"

The doctor slowly shook his head. "Can't say that it does, Smith. I have
always considered Venus as having an appearance peculiarly her own.
Why?"

The engineer started to answer, stopped, thought better of it, and
instead pointed out the half that was in shadow. "Why is it that we can
make out the black portion so easily?"

Kinney could answer this. "The fact is, it isn't really black at all,
but faintly lighted. Presumably it is star-shine."

"Star-shine!" echoed the architect, interested.

"Just that. You see," finished the doctor, "if that side is never turned
toward the sun, then it must be covered with ice, which would reflect
the star--"

"Ah!" exclaimed Smith with satisfaction. "I wasn't so crazy after all!
My notion was that the whole blamed thing is covered with ice!"

It looked reasonable. Certainly the entire sphere had a somewhat watery
appearance. It prompted the geologist to say:

"Kinney--if that reflection is really due to ice, then there must be
plenty of water vapor in the air. And if that's the case--"