eful and
productive work.--Yours sincerely,

ALFRED E. WALLACE.

PART VI

Some Further Problems

I.--Astronomy

Of the varied subjects upon which Wallace wrote, none, perhaps, came
with greater freshness to the general reader than his books written when
he was nearly eighty upon the ancient science of astronomy.

Perhaps he would have said that the "directive Mind and Purpose" kept
these subjects back until the closing years of his life in order that he
might bring to bear upon them his wider knowledge of nature, enlightened
by that spiritual perception which led him to link the heavens and the
earth in one common bond of evolution, culminating in the development of
moral and spiritual intelligences.

"Man's Place in the Universe" (1903) was in effect a prelude to "The
World of Life" (1910). Wallace saw afterwards that one grew out of the
other, as we find him frequently saying with regard to his other books
and essays.

As with Spiritualism, so with Astronomy, the seed-interest practically
lay dormant in his mind for many years; with this difference, however,
that temperament and training caused a speedy unfolding of his mind when
once a scientific subject gripped him, whereas with Spiritualism he felt
the need of moving slowly and cautiously before fully accepting the
phenomena as verifiable facts.

It was during the later period of his land-surveying, when he was
somewhere between the ages of 18 and 20, that he became distinctly
interested in the stars. Being left much alone at this period, he began
to vary his pursuits by studying a book on Nautical Astronomy, and
constructing a rude telescope.[55] This primitive appliance increased
his interest in other astronomical instruments, and especially in the
grand onward march of astronomical discovery, which he looked upon as
one of the wonders of the nineteenth century.

It was the inclusion of astronomy in lectures he delivered at Davos
which led him to extend his original brief notes into the four chapters
which form an important part of his "Wonderful Century." He freely
confessed that in order to write these chapters he was obliged to read
widely, and to make much use of friends to whom astronomy was a more
familiar study. And it was whilst he was engaged upon these chapters
that his attention became riveted upon the unique position of our planet
in relation to the solar system.

He had noticed that certain definite conditions appeared to