Punctuation, hyphenation, and spelling were made consistent when a predominant preference was found in the original book; otherwise they were not changed.

Simple typographical errors were corrected; unbalanced quotation marks were remedied when the change was obvious, and otherwise left unbalanced.

Illustrations in this eBook have been positioned between paragraphs and nearer to the text that references them.

Footnotes in this eBook have been collected and moved to the end of the book.

The Table of Contents entry for Problem II, Chapter II, referenced the wrong page; corrected here.