"Sand," said Roland.

"And now it is white, like a piece of pottery," she exclaimed.

"That is white clay," said he.

"Don't you want to take my place," said she, "if you will not
come with me?"

"No," said Roland. "Look down as long as you wish; I know pretty
well what you will see for some time to come. Has there been any
change?"

"The bottom is still white," she replied, "but it is glittering."

"That is white sand," said he. "The Artesian well which supplies
the works revealed to me long ago the character of the soil at
this spot, so that for a hundred feet or more I know what we may
expect to see."

She came out hurriedly. "When you begin to speak of wells," she
said, "I am frightened. If I should see water, I should lose my
head." She sat down and put her hand before her eyes. "My brain
is dazzled," she said. "I don't feel strong enough to believe
what I have seen."

Roland shut off the current and opened the screen. "Come here,
Margaret," he said; "this is the spot upon which the light was
shining. I think it will do you good to look at it. Tread upon