—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—In the text versions only, text in italics is delimited by
_underscores_.
—Silently corrected a few typos.
—Tweaked the order of the Table of Contents to match the text.
—Incorporated the “erratum” (from an inserted slip) into the text. The
erroneous Step 3 replicated Step 2.
—Inserted references to unreferenced endnotes at apparently-appropriate
places.