t those great books."

She put herself at ease in her chair like one who prepares to listen
quietly.

"Shall I tell you how the whole argument runs as I have arranged it? I
shall have to begin far away and come down to the subject by degrees."
He looked apologetic.

"Tell me everything; I have been waiting a long time."

David reflected a few moments and then began:--

"The first of my books as I have arranged them, considers what we call
the physical universe as a whole--our heavens--the stars--and discusses
the little that man knows about it. I used to think the earth was the
centre of this universe, the most important world in it, on account of
Man. That is what the ancient Hebrews thought. In this room float
millions of dust-particles too small to be seen by us. To say that the
universe is made for the sake of the earth would be something like
saying that the earth was created for the sake of one of these
particles of its own dust."

He paused to see how she received this.

"That ought to be a great book," she said approvingly. "I should like
to study it."

"The second takes up that small part of the universe which we call our
solar system and sums up the little we have learned regarding it. I
used to think the earth the most important part of the solar system, on
account of Man. So the earliest natural philosophers believed. That is
like believing that the American continent was created for the sake,
say, of my father's farm."

He awaited her comment.

"That should be a great book," she said simply. "Some day let me see
THAT."

"The third detaches for study one small planet of that system--our
earth--and reviews our latest knowledge of that: as to how it has been
evolved into its present stage of existence through other stages
requiring unknown millions and millions and millions of years. Once I
thought it was created in six days. So it is written. Do you believe
that?"

There was silence.

"What is the next book?" she asked.

"The fourth," said David, with a twinkle in his eye at her refusal to
answer his question, "takes up the history of the earth's surface--its
crust--the layers of this--as one might study the skin of an apple as
large as the globe. In the course of an almost infinite time, as we
measure things, it discovers the appearance of Life on this crust, and
then tries to follow the progress of Life from the lowest forms upward,
always upward, to Man: another time infinitely vast, ac