Transcriber's Note
Reading edition
1. Obvious errors in spelling and punctuation have been corrected.
2. Hyphenation has been made consistent where possible, using the form most prevalent in the book or, failing that, in other books of the period.
3. The following further changes have been made:
Page 186: "membraneous" to "membranous".
Page 269: "predicating" to "predicting".
Page 414: "sand crack" to "sandcrack".
4. The diagram on Page 24 is shown again on Page 28, as it was in the original work.