mbra," said the doctor. Then he altered his course
experimentally, and found a slightly darker path, but it soon began
changing again to grey.

"There is no use trying to keep in the umbra any longer. It is growing
too narrow. The penumbra will last quite a long time yet, but it will
gradually get fainter and fainter. We shall not plunge at once into the
dreadful light you fear so much. Keep your eyes glued to the Earth. I
can scarcely see Mars any longer. The whole field is getting blank and
white."

The rear vista was also growing a pale white, and I could distinguish
the form of the Earth as a darker object slightly larger than a full
moon when risen. But it was all growing dimmer and dimmer as the
penumbra faded toward the perfect light.

"Mars is completely gone now," said the doctor. "The field of the
telescope is one pale curtain of light. I have steered to the left to go
ahead of him now, as there is no longer any reason for going behind
him."

I heard him working at the telescope as if loosening it from its
fastenings, but I dared not take my eyes from the Earth to see what he
was doing. Presently he called out to me,--

"Make room down there. I must bring the instrument down and observe the
Earth now. Be careful you don't lose sight of her." But the instant he
removed the telescope from its bearings and uncovered his forward
window, I lost all view of the Earth. The new light now entering by his
window, from behind me, made it impossible to see so far.

"Too late!" I cried; "I have lost her! We are alone in limitless space,
without even the company of the planets!"

But while the doctor was carefully lowering the telescope, my eyes were
still searching, and presently I perceived a thin crescent of faintly
brighter light, growing gradually wider. It was like a new moon dimly
seen in a clear part of the sky when the afternoon sun is cloud-hidden.
The doctor stopped to look where I pointed it out to him, and then
changed the wheel a little.

"That is a thin slice of the illuminated part of the Earth," he said.
"We can no longer see the dark side which has been visible to us while
in the shadow. Fortunately our new course a little ahead of Mars will
give us a constant view of this thin crescent."

We now stood the instrument on end over the port-hole window, which
brought the small end near the aperture between the compartments. When
the doctor had secured a focus, he called me to look. The crescent was