ACKNOWLEDGMENTS 



It is a pleasure to express my gratitude to Mr. Vanderbilt for 

 his unfailing patience, helpful criticism and gracious generosity 

 which has made the prosecution of this research an unforgettable 

 privilege. 



I am also indebted to Dr. Herbert Putnam, Librarian of Con- 

 gress, and his staff assistants in the science, rare book and map 

 divisions, for exceptional research privileges in this institution, 

 and to my colleagues in the Asiatic, Australian, Oceanic, Euro- 

 pean, African, South and North American Museums for many 

 helpful courtesies, particularly in the location and examination of 

 rare materials and records. Mr. Ernest L. Crandall, of Washing- 

 ton, D. C, dean of the United States government photographic 

 experts, personally made the photographs in his private studio. 

 The illustrations were all made under my personal supervision; 

 the line drawings being carefully done to scale and verified by two 

 ladies who assist me. The Press of Whittet & Shepperson has been 

 especially helpful in the preparation of the plates in this volume. 



