Vlll PREFACE 



drawings, and my daughter Phyllis Seward has also given me 

 much help in preparing drawings from previously published 

 figures. 



In spite of the vigilance and wise counsel of many friends 

 numerous blemishes remain and for these the author is alone 

 responsible. 



A. C. SEWAKD. 



DOWNING COLLEGE LODGE, 

 February 10, 1917. 



NOTE. The letters A and B added to references in the footnotes 

 indicate that the works will be found in the Bibliographies at the end 

 of Volumes I and II. 



