474 



SCIENTIFIC RESULTS OF ZIEGLER POLAR EXPEDITION 



DIURNAL VARIATION IN TEMPERATURE 



The thermograms obtained at Teplitz Bay from October i, 1903, to April 30, 1904, at 

 which latter date the thermograph failed, have been reduced to the standard of the thermom- 

 eter used in the daily observations. By graphical methods the mean daily thermograms for 

 each month of record have been deduced ; the diurnal inequalities indicated by these monthly 

 mean daily curves are shown in the following summary, values greater than the mean of day 

 being indicated by plus quantities, and vice versa. The mean monthly values for the correspond- 

 ing period October, 1899, to April, 1900, as obtained by the Italian Expedition* are entered 

 herewith for the sake of comparison, the quantities having been reduced to Fahrenheit scale. 



Summary of mean monthly diurnal variation in temperature at Teplitz Bay 

 From thermograms October, 1903, to April, 1904 



The above series being of only seven months' duration, no very elaborate reductions are 

 possible. Analytical expressions representing the daily variation in temperature have been 

 derived from the results 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 tabulation, 

 while the curves computed from the same are shown in figure 2. 



* Osservazioni scientifiche esquite 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. ) 



