Transcriber’s note:
All instances of ‘disk’ changed to ‘disc’
Errata, instance of ‘disk’ on page 79 added, “—— 79. — 5. ⎭”
Page 11, ‘Years’ changed to ‘years,’ “130 years after Christ”
Page 20, ‘h e’ changed to ‘the,’ “would have as much the appearance”
Page 24, ‘cannon ball’ changed to ‘cannon-ball,’ “the time a cannon-ball would”
Page 63, comma changed to full stop after ‘Tutor,’ “Tutor. Why?”
Page 65, ‘a’ changed to ‘a,’ “carry a planet from A to a”
Page 74, ‘itaxis’ changed to ‘its axis,’ “if the earth revolve on its axis every”
Page 78, ‘Mercury’ struck after ‘Sun,’ “Sun, Venus, Mars, and Jupiter are known to revolve on their axes”