PREFACE TO 8th REVISED EDITION 



The present edition of the Smithsonian Physical Tables entails a consider- 

 able enlargement. Besides the insertion of new data in the older tables, about 

 270 new ones have been added. Their scope has been further broadened to 

 include many new tables relating to astrophysics, geophysics, meteorology, 

 geochemistry, atmospheric electricity, wireless, molecular and atomic data, etc. 



Many suggestions and data have been received : from the Bureau of Stand- 

 ards, the Coast and Geodetic Survey (magnetic data), the Geophysical Labora- 

 tory, Naval Research Laboratory, Department of Terrestrial Magnetism, 

 Harvard College Observatory, Eastman Kodak Co. (photographic data), 

 National Research Council (International Critical Tables) ; from Messrs. 

 Adams, White (Geophysical Laboratory), R. T. Birge, Briggs, Dellinger, 

 Deming (Bureau of Chemistry and Soils), Dorsey (I. C. T.), Fleming, For- 

 sythe, Hulburt, Lovejoy and Loomis (Eastman Kodak Co.), Kimball, Menzel, 

 van Maanen, Russell, Shapley, St. John, Wells, Wherry, and many others 

 whose names generally will be found with the corresponding data furnished. 

 To all these we are indebted. 



The changes in the domain of physics and allied branches have been so 

 radical and extensive that it has been difficult to do justice to the advances. 

 Further, it has been deemed essential to keep this volume in handy size, 

 referring the reader to the more extensive International Critical Tables or 

 to Landolt-Bornstein's Physikalisch-chemische Tabellen for more extensive 

 data. It has been inadvisable to delay the tables for revision in many places. 

 We will be grateful for criticisms, the notification of errors, and new data. 



Frederick Eugene Fowle. 

 astrophysical observatory, 

 Smithsonian Institution, 

 March, 1932. 



