Superscripts were used only as abbreviations for names and words, not in mathematical expressions, and have been printed as normal lower-case letters in the Plain Text version of this eBook. The Transcriber did not review the spelling of non-English words. Second page (unnumbered), last line: “with whom they abide.” The word shown here as “abide” was poorly printed and unclear. At the bottom of the Title page, the date is “1833”; at the bottom of the cover, the date is “1835”. Page 66: “piece of plane glass” was printed that way. Page 66: Transcriber added the comma in “and LR, LR the extreme red”. Page 70: Transcriber added italics to “makes _orange_”. Page 126: “on the 7th January, 1618” should be “1610”. Page 306 referred to Newton’s telescope being shown in “fig. 1”, but it actually is in “fig. 3” and is referenced that way in this eBook. Page 321: The opening parenthesis before “viz. one of those that go round another” has no matching closing parenthesis. Transcriber added a closing parenthesis after “round another planet”, but that may not be where it belongs.