ADVERTISEMENT TO FIFTH REMSED EDITION. 



The original edition of the Smithsonian Meteorological Tables was issued 

 in 1893, and revised editions were published in 1896, 1897. 1907, and 1918. A 

 fifth revised edition is here presented, which has been prepared under the 

 direction of Charles F. Mar\dn, Chief of the U. S. Weather Bureau, assisted 

 by Herbert H. Kimball, Senior ^Meteorologist of the same bureau. Officials of 

 the U. S. Bureau of Standards have been consulted relative to the value of 

 certain physical constants that enter into the calculation of the tables. All 

 errata thus far detected in the earlier editions have been corrected. 



The great development in the exploration of the free air to the height 

 of the tropopause and even beyond calls for an extension of some tables to 

 adapt them to the low temperatures and pressures experienced at these great 

 heights, and also for a distinction between the symbols for the acceleration of 

 gravity at the surface of the earth and in the free air. Also, the measurement 

 of heights as " geopotentials " in " dynamic meters " calls for five new tables. 

 The table of international meteorological symbols has been revised, and a 

 table of " International code for horizontal visibilit}' " has been added. Much 

 of the work of extension of old tables and the computation of new ones has 

 been done by the Aerological Division of the Weather Bureau. 



The complete revision of the " List of meteorological stations," including 

 an alphabetical arrangement by continents, countries, and stations, has been 

 effected by Mr. W. \Y. Reed of the Climatological Division, U. S. Weather 

 Bureau. 



Charles G. Abbot, 



Secretary. 

 Smtthsoniax Institution, 

 March 21, igsi. 



