Transcribers' Note
Punctuation 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.
Some illustrations have been slightly repositioned to improve their appearance in eBooks.
Page 76: "eight tenths of an inch" may be a misprint for "eight ten-thousandths of an inch".
Page 100: "inhaled air" was misprinted as "inhaled aid".
Page 104: "would send the stream" was misprinted as "sent".
Page 113: "Secretely" was printed that way.
Page 209: "psycologists" was printed that way.