30 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 90 



The pressure and temperature before 1920 were reduced by B. J. 

 Birkeland to a uniform series, the details of which are given in 

 Geofysiske Publikationer, volume 3, no. 9, Utgit av den Geofysiske 

 Kommission. The results were derived mainly from Esmark's obser- 

 vations 1816-1838, observations at the Observatory 1836-1865, and 

 observations at the Meteorological Institute 1866- 1920. The obser- 

 vations 1866-1920 were published in volume 79, Smithsonian Misc. 

 Coll., and those preceding 1866 are given in part III. 



Time. 



The observations were made three times daily and part of the 

 time five times daily, but at different hours. These are re- 

 duced to a uniform series. The later observations were at 

 8 b , 14 11 , and I9 h or 20 h , Central European time. 

 Pressure. 



The pressure was corrected to o° C. and to normal gravity and 

 reduced to the level of 24.9 m. 

 Temperature. 



The mean temperature was derived mostly from the three obser- 

 vations daily by the formula m=l(l + ll + IIl) +C, in 

 which C was a correction determined for each month sepa- 

 rately and for each series of observations. 

 Site: The exposures were made in a window shelter. 

 Remarks. 



The data before 1866 are given in part III. The data 1866- 1920 

 are given in volume 79, Smithsonian Misc. Coll. The data 

 1921-1930 are in part I of this volume. 



POLAND 



Authority. 



Institute Central Meteorologique, Warsaw. Continuation of 

 observations at stations published in volume 79, Smithsonian 

 Misc. Coll. 



WARSZAWA (WARSAW) 



The meteorological station was removed in 1923 from the " Societe 

 Scientifique," Lat. 52 13' N., Long. 21 1' E., H b =i33 m, to the 

 station " l'Usine des Eaux," Lat. 52 13' N., Long. 21 3' E., H b = 

 88.3 m. The pressure from 1923 to 1930 was corrected to the old 

 height of 133 m. 



