. In addition to his
own personal knowledge, however, some interesting comparisons are drawn
between the accounts given by early explorers and the impressions left
on his own mind by the same places and people. On the publication of
this work, in 1869, extensive and highly appreciative reviews appeared
in all the leading papers and journals, and to-day it is still looked
upon as one of the most trustworthy and informative books of travel.

When the "Malay Archipelago" was in progress, a lengthy article on
"Geological Climates and the Origin of Species" (which formed the
foundation for "Island Life" twelve years later) appeared in the
_Quarterly Review_ (April, 1869). Several references in this to the
"Principles of Geology"--Sir Charles Lyell's great work--gave much
satisfaction both to Lyell and to Darwin. The underlying argument was a
combination of the views held by Sir Charles Lyell and Mr. Croll
respectively in relation to the glacial epoch, and the great effect of
changed distribution of sea and land, or of differences of altitude, and
how by combining the two a better explanation could be arrived at than
by accepting each theory on its own basis.

His next publication of importance was the volume entitled
"Contributions to the Theory of Natural Selection," consisting of ten
essays (all of which had previously appeared in various periodicals)
arranged in the following order:

1. On the Law which has regulated the Introduction of New Species.

2. On the Tendency of Varieties to depart indefinitely from the Original
Type.

3. Mimicry, and other Protective Resemblances among Animals.

4. The Malayan Papilionidae.

5. Instinct in Man and Animals.

6. The Philosophy of Birds' Nests.

7. A Theory of Birds' Nests.

8. Creation by Law.

9. The Development of Human Races under the Law of Natural Selection.

10. The Limits of Natural Selection as applied to Man.

His reasons for publishing this work were, first, that the first two
papers of the series had gained him the reputation of being an
originator of the theory of Natural Selection, and, secondly, that there
were a few important points relating to the origin of life and
consciousness and the mental and moral qualities of man and other views
on which he entirely differed from Darwin.

Though in later years Wallace's convictions developed considerably with
regard to the spiritual aspect of man's nature, he never deviated from
the ideas laid down in the