viii AUTHOR'S PREFACE 



HowLAND Wood, Curator, and Bannock L. Belden, Secretary of 



the American Numismatic Society, 

 e. r. holden, 

 Henry Walters, 

 Gardner C. Teall, 

 Dr. Louis Livingston Seaman, 



William S. Page, for many data on Congo and Belgian ivory, 

 E. T. Newell, President of the American Numismatic Society, 

 Prof. James S. Macgregor, Department of Physics, Columbia 



University, 

 Messrs. Tiffany & Co., 

 Albert A. Southwick, and Arthur L. Barney, for much aid in 



obtaining photographs, 

 Charles Byron Blake, 

 Dr. Charles S. Braddock, Jr., 

 George E. Ashby, 

 Ramon Guiteras, M.D., 

 Thomas W. Ashwell, 

 Miss Mary A. Dickerson, Editor of the Journal of the American 



Museum of Natural History, to whom is due the suggestion 



that led to the preparation of this volume; all of New York 



City. 

 Dr. Stewart W. Culin, Oriental Archaeologist of the Brooklyn 



Institute Museum, Brooklyn, N. Y., 

 Dr. James B. Nies, Assyriologist, Brooklyn, N. Y., 

 Dr. John D. Clark, State Geologist, Albany, N. Y., 

 Dr. Henry Lee Smith, President, and Henry R. Howland, 



Superintendent, Buffalo Society of Natural History, 

 Mrs. Elsie W. Southwick Clark, Miniaturist, Orange, N. J., 

 J. W. Baer, Miniaturist, East Orange, N. J., 

 Lieut. G. T. Emmons, Greenholm, Princeton, N. J., 

 Prof. Edward C. Kirk, University of Pennsylvania, 

 H. J. Heinz, Pittsburgh, Pa., 



Prof. A. V. Williams Jackson, Columbia University, 

 Dr. W. D. Matthew, Curator, American Museum of Natural 



History, 

 Herbert Lang, Leader of Congo Expeditions, American Museum 



of Natural History, 

 Miss Ethel Quinton Mason, 

 W. Sew ALL, 



