Transcriber's Note:
- Minor typographical errors have been corrected without note.
- Punctuation and spelling were made consistent when a predominant form was found in this book; otherwise they were not changed.
- Ambiguous hyphens at the ends of lines were retained.
- Duplicated section headings have been omitted.
- The Flowering Almond illustration has been moved from page 195 to page 193.
- The Contents table was added by the transcriber.