They all hastened to the windows to look, and although Trot and Cap'n Bill could see nothing but a solid dome above the castle--perhaps because it was so far away from them--the sharp eyes of Aquareine were not to be deceived.
"Yes," she announced, "there is surely an opening in the center of the great dome.

A little thought must convince us that such an opening is bound to exist, for otherwise the water confined within the dome would not be fresh or clear." "Then if we could escape from this castle, we could swim up to the hole in the dome and get free!" exclaimed Trot.
"Why, Zog has probably ordered the opening well guarded, as he has all the other outlets," responded the Queen.

"Yet it may be worth while for us to make the attempt to get back into the broad ocean this way.

The night would be the best time, when all are asleep, and surely it will be quicker to reach the ocean through this hole in the roof than by means of the long, winding passages by which we entered." "But we will have to break out of the castle in some way," observed Cap'n Bill.
"That will not be difficult," answered Aquareine.

"It will be no trouble for me to shatter one of these panes of glass, allowing us to pass out and swim straight up to the top of the dome." "Let's do it now!" said Trot eagerly.
"No, my dear, we must wait for a good opportunity when we are not watched closely.