--Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
--Silently corrected a few palpable typos, leaving period spellings
unchanged.
--In the text versions only, text in italics is delimited by
_underscores_.
--Added subheadings in the text to match entries in the Table of
Contents.
--Added captions to illustrations based on the attributions in front
matter.