18 



SOLAR DIURNAL VARIATION 



Annual Inequality in the Diurnal Variation of the Dip. The comparison of the 

 above diurnal variations for summer and winter, with that of the whole year, is 

 given in the following Table. 



The tabular quantities are exhibited in diagram A. 



(A). SEMI-ANNUAL INEQUALITY IN THE DIURNAL VARIATION OF THE INCLINATION. 



0" 



22 24" (+21.1-) 



Philadelphia mean time. 



