The only way, then, to gain entrance to the sunken island was to break the charm that held the door fast shut.

If this could be done no magic would be required to open it.
The next day the Sorceress and the Wizard again entered the boat and made it submerge and go to the marble door, which they tried in various ways to open, but without success.
"We shall have to abandon this attempt, I think," said Glinda.

"The easiest way to raise the island would be for us to gain admittance to the Dome and then descend to the basement and see in what manner Coo-ee-oh made the entire island sink or rise at her command.

It naturally occurred to me that the easiest way to gain admittance would be by having the boat take us into the basement through the marble door from which Coo-ee-oh launched it.

But there must be other ways to get inside the Dome and join Ozma and Dorothy, and such ways we must find by study and the proper use of our powers of magic." "It won't be easy," declared the Wizard, "for we must not forget that Ozma herself understands considerable magic, and has doubtless tried to raise the island or find other means of escape from it and failed." "That is true," returned Glinda, "but Ozma's magic is fairy magic, while you are a Wizard and I am a Sorceress.