476 SCIENTIFIC RESULTS OF ZlEGLERi POLAR EXPEDITION 



Diurnal Variation in Atmospheric Pressure 

 The barograms made at Teplitz Bay during the period of regular daily observation have 

 been reduced to the standard of the mercurial barometer used. By graphical methods the 

 mean daily curves for each month have been deduced ; the diurnal inequalities so obtained are 

 exhibited in the table following, pressure greater than the mean of day being indicated by plus 

 signs, and vice versa. The mean monthly values for the corresponding period October, 1899, to 

 April, 1900, as obtained by the Italian Expedition* are entered for the sake of comparison, 

 the quantities having been reduced to English measure. 



Summary of mean monthly diurnal variation in atmospheric pressure at Teplitz Bay 

 From barograms October, 1903, to April, 1904 



In view of the fact that observations for only seven months of the year are available, no 

 very elaborate reduction of the above diurnal variation quantities has been attempted. Ana- 

 lytical expressions representing the daily variation in atmospheric pressure indicated by these 

 results have been derived by means of Bessel's periodic function (see page 289) to terms of the 

 third order. The resulting amplitudes and phase angles are shown in the following tabula- 

 tion, and the diurnal variation curves computed from the same are represented graphically in 

 figure 3. 



* Osservazioni scientifiche esequite durante la spedizione Polare di S. A. R. Luigi Amedeo di Savoia, Duca 

 degli Abruzzi, 1899-1900. Milan, 1903. Pp. 331-357. (Relazione sulle osservazioni meteorologiche fatta dal 

 Professore Giovanni Battista Rizzo. ) 



