light!"

"Roland," said Margaret, "you are crazy! Perhaps it is water which fills
that cave, or whatever it is."

"Not at all," said Roland. "It presents no appearance of water, and when
the camera came up it was not wet. No; it is a cave of light."

He sat for some minutes silently gazing out of the window. Margaret drew
her chair closer to him. She took one of his hands in both of hers.

"Look at me, Roland!" she said. "What are you thinking about?"

He turned his face upon her, but said nothing. She looked straight into
his eyes, and she needed no Artesian ray to enable her to see through
them into his innermost brain. She saw what was filling that brain;
it was one great, overpowering desire to go down to the bottom of that
hole, to find out what it was that he had discovered.

"Margaret, you hurt me!" he exclaimed, suddenly. In the intensity of the
emotion excited by what she had discovered, her finger-nails had nearly
penetrated through his skin. She had felt as if she would hold him and
hold him forever, but she released his hand.

"We haven't talked about that button-hole machine," she said. "I want
your opinion of it." To her surprise, Roland began immediately to
discuss the new invention of which she had spoken, and asked her to
describe it. He was not at all anxious now to tell Margaret what he was
thinking of in connection with the track of the shell.

CHAPTER XVII. CAPTAIN HUBBELL DECLINES TO GO WHALING

The most impatient person on board the Dipsey was Captain Jim Hubbell.
Sarah Block was also very anxious to go home as soon as matters could
be arranged for the return journey, and she talked a great deal of the
terrible fate which would be sure to overtake them if they should be so
unfortunate as to stay until the season of the arctic night; but, after
all, she was not as impatient as Captain Hubbell. She simply wanted
to go home; but he not only greatly desired to return to his wife and
family, but he wanted to do something else before he started south; he
wanted to go whaling. He considered himself the only man in the whole
world who had a chance to go whaling, and he chafed as he thought of the
hindrances which Mr. Gibbs was continually placing in the way of this,
the grandest of all sports.

Mr. Gibbs was a mild man, and rather a quiet one; but he thoroughly
understood the importance of the investigations he was pursuing in the
polar sea, and placed full value upon the opportunity whi