Many kind friends have given me information about glaciÈres or assistance in my work. I am especially indebted to Mr. Robert Butler, of San JosÉ, Cal.; Mr. F. H. Cushing, of Washington, D. C.; Professor Charles E. Fay, of Tufts College, Mass.; Professor Eberhard Fugger, of Salzburg, Austria; Mr. Alois F. Kovarik, of Decorah, Iowa; Monsieur E. A. Martel, of Paris, France; Mr. John Ritchie, Jr., of Boston, Mass.; Professor I. C. Russell, of Ann Arbor, Mich.; Miss H. Varena, of Wiesbaden, Germany; and Miss Mary Coxe, Mr. G. L. Farnum, Mr. J. E. Farnum, Mr. F. L. Garrison, Mr. W. C. Hall, Mr. E. I. H. Howell, Mrs. Horace Jayne, Mr. W. E. Meehan, Mr. C. J. Nicholson, Mr. G. B. Phillips, Mr. Bunford Samuel, Mr. W. W. Wagner, and Dr. W. H. Wahl, of Philadelphia. I wish to acknowledge also the help I have derived from the BibliothÈque Nationale and the library of the British Museum.

E. S. B.

Philadelphia, February the 10th, 1900.