Transcriber’s Notes

Retained publication information from the printed edition: this eBook is public-domain in the country of publication.
Some captions describing separately placed images were split, removing redundant relative clauses like “Above” or “To the right is...”
In the text version only, underlined or italicized text is delimited by _underscores_.
Where possible, UTF superscript and subscript numbers are used; some e-reader fonts may not support these characters.
In the text versions only, other superscript text is preceded by caret and delimited by ^{brackets}.
In the text versions only, other subscripted text is preceded by underscore and delimited by _{brackets}.
The Table of Contents lists pages and illustrations in all three volumes:
Volume 1
Volume 2
Volume 3
These links can be made to function on local copies of the files.