I! 



DISCUSSION OF THE HORIZONTAL COMPONENT 



In the preceding table the normals for the summer half year comprise the months 

 between April and September inclusive; those for the winter half year comprise 

 the months between October and March inclusive. 



The following table contains the mean values of the normals for each month and 

 season. 



Regular Solar-Diurnal Variation of th Horizontal Force.— -If we subtract the 

 hourl) normals of Table 1. from their respective monthl) mean value as given in 

 Table II., the difference (in scale divisions) will represent the regular solar-diurnal 



