Transcriber's Notes

The following changes have been made to the text as printed.

1. Illustrations and end-of-page footnotes (marked with an asterisk) have been located in appropriate paragraph breaks.

2. Where a word is used repeatedly in the same way, spelling and hyphenation have been made consistent, preferring the form most often used in the printed work, or failing that the more usual form in general use at the time of publication. No typographical change has been made within direct quotes from other works.

3. The spelling of the following names has been changed to agree with normal usage at the time of the original publication:

4. Index: the following entries have been amended in line with the corresponding body text:

On Page 137, "[south latitude 40°]" should no doubt read "south latitude 4°". No change has been made.