Some corrections were made to the original text. In particular, punctuation was corrected without further note. Inconsistent spelling and hyphenation was retained unless noted otherwise. There were two [Notes 189] in the original; this was retained as printed. Spelling of Index entries was changed to reflect the body text where inconsistencies were found. Index page numbers were corrected where errors were found. Further corrections are noted below:
p. [50] 0·005·1449 -> 0·0051449
p. [61] 24,000 -> 240,000
p. [62] M. Leverrier -> M. Le Verrier
p. [84] in mean solar day -> in a mean solar day
p. [96] syzigies -> syzygies
p. [115] arrising -> arising
p. [120] Herchel -> Herschel
p. [123] generally know -> generally known
p. [159] Fraunhoffer’s -> Fraunhofer’s