—Retained publication information from the printed edition: this eBook
is public-domain in the country of publication.
—Corrected a few palpable typographical errors.
—The “List of Specimens” was not consistent with figure captions; there
was no obvious fix, and none was attempted.
—Added one section heading, “3. Iroquois Weighted Drill” to make section
headings (but not section order) consistent with the introductory
classification.
—In the text versions only, text in italics is delimited by
_underscores_.