ADVERTISEMENT. 



In connection with the system of meteorological observations established by 

 the Smithsonian Institution about 1850, a series of meteorological tables was 

 compiled by Dr. Arnold Guyot, at the request of Secretary Henry, and the first 

 edition was published in 1852. Though primarily designed for meteorological 

 observers reporting to the Smithsonian Institution, the tables were so widely used 

 by physicists that it seemed desirable to recast the work entirely. It was decided 

 to publish three sets of tables, each representative of the latest knowledge in its 

 field, and independent of one another, but forming a homogeneous series. The 

 first of the new series, Meteorological Tables, was published in 1893, tne second, 

 Geographical Tables, in 1894, and the third, Physical Tables, in 1896. In 1909 

 yet another volume was added, so that the series now comprises : Smithsonian 

 Meteorological Tables, Smithsonian Geographical Tables, Smithsonian Physical 

 Tables, and Smithsonian Mathematical Tables. 



The fourteen years which had elapsed in 1910 since the publication of the first 

 edition of the Physical Tables, prepared by Professor Thomas Gray, had brought 

 such changes in the material upon which the tables must be based that it became 

 necessary to make a radical revision for the 5th revised edition issued in 1910. 

 That revision has been still further continued for the present sixth edition. 



CHARLES D. WALCOTT, 

 Secretary of the Smithsonian Institution. 

 June, 1914. 



