a great
height--except at one narrow end which was open to a view of the sea.
You could imagine it a council-place or concert-hall for giants, and the
rock table in the centre the stage for performers or the stand for the
speaker.

We asked our guides why it was called the Whispering Rocks; and they
said, "Go down into it and we will show you."

The great bowl was miles deep and miles wide. We scrambled down the
rocks and they showed us how, even when you stood far, far apart from
one another, you merely had to whisper in that great place and every one
in the theatre could hear you. This was, the Doctor said, on account of
the echoes which played backwards and forwards between the high walls of
rock.

Our guides told us that it was here, in days long gone by when the
Popsipetels owned the whole of Spidermonkey Island, that the kings were
crowned. The ivory chair upon the table was the throne in which they
sat. And so great was the big theatre that all the Indians in the island
were able to get seats in it to see the ceremony.

They showed us also an enormous hanging stone perched on the edge of a
volcano's crater--the highest summit in the whole island. Although it
was very far below us, we could see it quite plainly, and it looked
wobbly enough to be pushed off its perch with the hand. There was
a legend among the people, they said, that when the greatest of all
Popsipetel kings should be crowned in the ivory chair, this hanging
stone would tumble into the volcano's mouth and go straight down to the
centre of the earth.

The Doctor said he would like to go and examine it closer.

And when we were come to the lip of the volcano (it took us half a day
to get up to it) we found the stone was unbelievably large--big as a
cathedral. Underneath it we could look right down into a black hole
which seemed to have no bottom. The Doctor explained to us that
volcanoes sometimes spurted up fire from these holes in their tops; but
that those on floating islands were always cold and dead.

"Stubbins," he said, looking up at the great stone towering above us,
"do you know what would most likely happen if that boulder should fall
in?"

"No," said I, "what?"

"You remember the air-chamber which the porpoises told us lies under the
centre of the island?"

"Yes."

"Well, this stone is heavy enough, if it fell into the volcano, to break
through into that air-chamber from above. And once it did, the air would
escape and the