PREFACE. Vll 



tituto Chemico, Rome ; Biblioteca Marucelliana, Florence ; Biblioteca 

 Nazionale, Florence ; Biblioteca Brera, Milan ; Biblioth^que Royale, 

 Brussels ; Bibliotheque Nationale, Paris ; British Museum, London ; 

 Harvard University, Cambridge ; Public Library, Boston ; Massachu- 

 setts Institute of Technology, Boston ; Society of Natural History, Bos- 

 ton ; Public Library, New York ; Columbia University, New York ; 

 Franklin Institute, Philadelphia ; Academy of Natural Sciences, Phila- 

 delphia ; as well as the following in Washington, D. C. : U. S. De- 

 partment of Agriculture, U. S. Coast and Geodetic Survey, U. S, Geo- 

 logical Survey, Library of Congress, U. S. Naval Observatory, U. S. 

 Navy Department, U. S. Patent Office, Smithsonian Institution, Surgeon- 

 General's Office of the U. S. Army, U. S. War Department, U. S. Weather 

 Bureau. 



Henry Carrington Bolton. 



Washington, D. C. 



