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. All of the above have responded in a most gratifying manner to requests for information, some of them taking the trouble to prepare long communications, which have been indispensable in the preparation of the following article and which the writer cherishes as among his most valued possessions. All quotations credited to them in this article have been taken from letters. Received by the writer since December, 1912.