—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—Corrected a few palpable typographical errors.
—Placed illustration captions below the corresponding illustration.
—Modified references to illustration locations to correspond to the
reality of a flowing eText, e.g. “shown on the opposite page” might be
converted to “shown below” or “shown here”.
—In the text versions only, text in italics is delimited by
_underscores_.