PREFACE TO THE STH REVISED EDITION. 



The present Smithsonian Physical Tables are the outcome of a radical revision 

 of the set of tables compiled by Professor Thomas Gray in 1896. Recent data 

 and many new tables have been added for which the references to the sources 

 have been made more complete; and several mathematical tables have been 

 added, some of them especially computed for this work. The inclusion of these 

 mathematical tables seems warranted by the demand for them. In order to pre- 

 serve a uniform change of argument and to facilitate comparison, many of the 

 numbers given in some tables have been obtained by interpolation in the data 

 actually given in the papers quoted. 



Our gratitude is expressed for many suggestions and for help in the improve- 

 ment of the present edition : to the U. S. Bureau of Standards for the revision of 

 the electrical, magnetic, and metrological tables and other suggestions ; to the 

 U. S. Coast and Geodetic Survey for the revision of the magnetic and geodetic 

 tables ; to the U. S. Geological Survey for various data ; to Mr. Van Orstrand for 

 several of the mathematical tables ; to Mr. Wead for the data on the musical 

 scales ; to Mr. Sosman for the new physical-chemistry data ; to Messrs. Abbot, 

 Becker, Lanza, Rosa, and Wood ; to the U. S. Bureau of Forestry and to others. 

 We are also under obligation to the authors and publishers of Landolt-Bornstein- 

 Meyerhoffer's Physikalisch-chemische Tabellen (1905) and B. O. Peirce's Mathe- 

 matical Tables for the use of certain tables. 



It is hardly possible that any series of tables involving so much transcribing, 

 interpolation, and calculation should be entirely free from errors, and the Smith- 

 sonian Institution will be grateful, not only for notice of whatever errors may be 

 found, but also for suggestions as to other changes which may seem advisable for 

 later editions. 



F. E. FOWLE. 



ASTROPHYSICAL OBSERVATORY 



OF THE SMITHSONIAN INSTITUTION, 



June, 1910 



PREFACE TO THE 6xn REVISED EDITION. 



The revision commenced for the fifth edition has been continued ; a large pro- 

 portion of the tables have been rechecked, typographical errors corrected, later 

 data inserted and many new tables are added, including among others a new set of 

 wire tables from advance sheets courteously given by the Bureau of Standards, 

 new mathematical tables computed by Mr. Van Orstrand and those on Rontgen 

 rays and radioactivity. The number of tables has been increased from 335 to 

 over 400. We express our gratitude to the Bureau of Standards, to the Geophysical 

 Laboratory, the Geological Survey, and to those who have helped through sug- 

 gested improvements, new data, or by calling our attention to errors in the earlier 

 editions. 



F. E. FOWLE. 

 ASTROPHYSICAL OBSERVATORY 

 OF THE SMITHSONIAN INSTITUTION, 

 October, 1913. 



