could see the stars distinctly with the
unassisted eye. But from March 21st to September 21st we cannot do that
because of continuous daylight. Now you are probably aware that looking
up from the bottom of a deep well or shaft in the daytime, the stars are
visible, even in the sunlight. And that is what I purpose doing."

"Well, and where is your shaft that you intend looking up through?"
inquired Dr. Jones.

The Professor significantly laid his hand upon the zinc tube which
enveloped the flagstaff. "O ho!" cried the Doctor, "why did not I think
of that?"

We should have explained before that the spiral stairs ran up between
two zinc tubes, the one six feet in diameter, and the other two feet in
diameter. The latter surrounded the mast, and after the globe should
rise from the flagstaff this tube would indeed be a shaft two hundred
feet in depth, or two hundred and ten feet, for it extended to the top
of the roof of the observatory.

Accordingly, the burners were lighted, the globe arose until the ball of
the mast was just below the level of the floor of the engine-room. Upon
looking through the tube after all light had been excluded from the
engine-room, a bright star could be seen shining down upon them with
resplendent brilliancy.

"Now, Will," cried Professor Gray, "I wish you could go up and lower a
plumb-line from the exact center of the top of the shaft. I want to see
if our tube stands perpendicularly. If it does, and the plumb-line
points straight through the center of it to yonder star, then we are at
the exact spot we seek."

The line was lowered, and after a little adjustment of the cables, the
lower end of the plumb-line passed through the exact center of the tube.
The Professor ran his eye up the line and smiled with satisfaction.

"Look at it, Doctor," he said.

"Well, that is wonderful!" cried Dr. Jones. "Look at it Fred, Denison.
The line runs precisely in alignment with the star."

"And now," said Professor Gray, after all had verified this last
statement, "let's not lose a moment's time. Get your camera out. We want
a twenty-four hours' exposure through our shaft, and photograph that
star. If we be exactly at the Pole, it will describe a perfect circle
upon the sensitive plate. If we are not so located, the line upon the
plate will form an ellipse."

The camera was set as suggested by the Professor, and then the party
retired for the night. We say "night," but the reader will constantly