Transcribers’ Notes
Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in this book; otherwise they were not changed.
Simple typographical errors were corrected; occasional unbalanced quotation marks retained.
Ambiguous hyphens at the ends of lines were retained.
Illustrations were printed mid-paragraph but have been moved between paragraphs, usually near to text that references them.
Footnotes have been collected and repositioned just before the Index.
Some in-line paragraph headings are in boldface and some are in italics; this emphasis has been retained.
Index not checked for proper alphabetization or correct page references, but a reference to page 274 was a typographical error and has been changed to 174.
Page 155: Text refers to c c′ in Figs. 38–39, but neither figure appears to contain a c′ label.