vi EDITORIAL NOTE 



For many of the stations averages of the series, or normals, were 

 given by the compilers. For others they were computed by the writer 

 and his assistants. 



Data for any part of the period 1921-1930 printed in volume 79 

 have been revised and reprinted in this volume, part I. 



The Ocean and Sea-Level data for land stations, part II, are classi- 

 fied under grand divisions beginning with the Pacific Ocean and 

 progressing from west to east. The individual stations are classified 

 by latitude beginning with the most northerly station in each grand 

 division and proceeding southward. 



The supplementary data, part III, are classified alphabetically by 

 grand divisions, by countries, and by stations in the same manner 

 as in Smithsonian Misc. Coll., volume 79 and in part I of this volume. 



In the data in volume 79 there were mistakes in observing, in com- 

 puting, in copying, and in printing, so that each country has been 

 asked to revise the data printed in that volume. Many of the services 

 have kindly undertaken this work, and it has resulted in a long list 

 of errata, some of which were published in May 1929, and others are 

 given in part IV of this volume. 



In the appendix are given the sun-spot data for 1 921 -1930 and 

 solar-radiation values derived from observations at three solar obser- 

 vatories as published in volume V of the Annals of the Astrophysical 

 Observatory of the Smithsonian Institution, page 278, table 45, headed 

 " Preferred Solar Constants. Monthly Means." 



