The following misprints and misspellings are noted or have been corrected in the text
Page 38: Superscript "1" changed to an inline fraction "1/8" in "50,000 prick-marks 1/8 inch apart".
Page 55: "corp" changed to "corps" in "a corps of inventors".
Page 145: "populsion" changed to "propulsion" in "for its own propulsion".
Page 173: "searchlight" changed to "search-light" in "when a search-light alone", to make the latter usage consistent throughout the book.
Page 206: "two" changed to "too" in "the reversal being too sudden".
Page 244: According to the 1911 Encyclopædia Britannica, "Kleingert" is the correct spelling of the name of the German who invented the "first practical diving helmet". More modern books, however, use a different spelling, referring to (Karl Heinrich) Klingert.
Page 250: "Saint Goubin" changed to "Saint Gobain" in "by Saint Gobain, of Paris".
Page 266: "overburden" changed to "over-burden" in 'removing the "over-burden" of surface mines' to make the latter usage consistent throughout the book.