The Editor of the Scientific American receives during the year thousands of inquiries from readers and correspondents covering a wide range of topics. The information sought for, in many cases, can not readily be found in any available reference or text-book. It has been decided, therefore, to prepare a work which shall be comprehensive in character and which shall contain a mass of information not readily procured elsewhere. The very wide range of topics covered in the Scientific American Reference Book may be inferred by examining the index and table of contents. This work has been made as nontechnical as the subjects treated of will admit, and is intended as a ready reference book for the home and the office. It is possible that in some of the tables published in the book certain inconsistencies may be observed. Such a condition of affairs is in some cases inevitable. In procuring the figures, for example, from different Departments of the Government, with reference to any subject, it has been found that statistics vary in certain particulars. These variations are due to the different methods of tabulation, or to some different system by means of which the figures have been arrived at. In a number of cases these discrepancies will be noted in the book, but they are not to be regarded as errors.

The debt for advice and help has been a heavy one. The compilation of this book would have been impossible without the cordial cooperation of government officials, who have been most kind. Our thanks are especially due to the Hon. O. P. Austin, Chief of the Bureau of Statistics, Department of Commerce and Labor; to the Hon. S. N". D. North, Director of the Census; Prof. John C. Monaghan, Editor of the Consular Reports; Hon. Eugene Tyler Chamberlain, Commissioner Bureau of Navigation; Dr. Marcus Benjamin, of the Smithsonian Institution; Major W. D. Beach, IT. S. A., of the General Staff; Rear-Admiral Charles O'Neil, late Chief of Bureau of Ordnance, U. S. N.; Hon. S. I. Kimball, General Superintendent, Life Saving Service; the Director of the Mint, Capt. Seaton Schroeder, U. S. N., Chief Intelligence Officer, U. S. N.; many examiners in the Patent Office; Hon. Willis L. Moore, Chief of the Weather Bureau; many officials of the Agricultural Department; Hon. Carroll D. Wright, Commissioner Bureau of Labor; Hon. George M. Bowers, and Mr. A. B. Alexander, of the Bureau of Fisheries; Prof. Charles Baskerville, Ph.D.; Edward W. Byrn, of Washington; Dr. George F. Kunz, Hon. S. W. Stratton, of the Bureau of Standards, and many others.

We are also indebted to the J. B. Lippincott Co. for permission to use diagrams of Geometrical Constructions; to HazelPs Annual, Whittaker's Almanac, and the "Daily Mail Year Book." A number of our diagrams are from the "Universal-Taschen Atlas" of Prof A. L. Hichrnann. Our matter on the "Arctic Regions" is translated from Dr. Hermann Haack's "Geographen-Kalender." For a number of our tables we must thank the excellent pocket books of D. K. Clark and Philip E. Bjorling, and we are also indebted to the Year Book issued by our esteemed English contemporary "Knowledge."

It is hoped that this work will save many fruitless searches through works of reference, as the aim of the compilers has been to obtain matter which is not readily available elsewhere.

New York, October 15, 1904.