CHAPTER I. Page

Introductory Remarks1

CHAPTER II.

Fact of Variation7
As a matter of experience 8
As probable from analogy 10

CHAPTER III.

Causes of Variation19
§ 1. Climatal causes generally (whether dependent
upon latitude or upon altitude) 23
§ 2. Temporary heat or cold, of an unusual degree 42
§ 3. Nature of the country, and of the soil 46
§ 4. Isolation; and exposure to a stormy atmosphere 70

CHAPTER IV.

Organs and Characters of Variation95

CHAPTER V.

Geological Reflections111

CHAPTER VI.

The Generic Theory157

CHAPTER VII.

Conclusion181