Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. What value the book may possess is a question in no degree involving that of the year in which it was written. No scientific experiments are required for its subject, no geographical discoveries; so that to all practical intents and purposes it is, after all, a new one. While revising, I have endeavoured to avoid adopting anything from the authors named, unless in the form of a brief quotation.