"I am not perfectly satisfied as to the location of our pole being exactly correct. And, to tell you the truth, it has been demonstrated that the Pole is not a fixed, unchangeable spot, but really swings about in a circle, varying from six to thirty feet in diameter, just as the upper end of the stem of a spinning top does when it begins to run down or lose its momentum. Now I am positive that our flagstaff stands within this circle. But I would like, by another very satisfactory experiment, to verify the one we have already made. It will require another twenty-four hours." "By all means, Professor," answered Dr. Jones, "do so. Let us do everything possible to establish the fact that we are scientifically correct in our location of the Pole. What would you have us do now?" "I will explain what I intend doing, and then we will understand and we can work intelligently together. I wish to photograph the stars directly above our heads. If we were here during the winter season, when the sun was below the horizon, we 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."