to greet the eye now. It was even unlike a trip in a balloon, for in
that sort of air-craft, at least for a time, a glimpse of the earth can
be had. Now there was nothing but a white blanket of mist to be seen,
which rolled this way and that. Occasionally it was dispelled, and the
full, golden sunlight bathed the projectile. The earth had long since
dropped out of sight, for it required only a few seconds to put the
_Annihilator_ high up in a position where even the most intrepid
balloonist had never ventured.

Mark and Jack sat for a few minutes in the pilot-house, looking out
into the ether. But they soon tired of seeing absolutely nothing.

"I wonder what we'll do when we get to the moon?" asked Jack of his
chum.

"Why, I suppose you'll make a dive for a hatful of diamonds, won't you?
That is, if you still believe that Martian newspaper account."

"I sure do."

The boys found the two professors busy adjusting some of the delicate
scientific instruments with which they expected to make observations on
the trip, and after they reached the moon.

"What is your opinion, Professor Roumann, of the temperature at the
moon's surface?" asked Mr. Henderson.

"I am in two minds about it," was the reply. "A few years ago, I see by
an astronomy, Lord Rosse inferred from his observations that the
temperature rose at its maximum (or about three days after full moon)