24 



THE ROYAL SOCIETY OF CANADA 

 Table V. 



Fourier Co-efficients. Horizontal Force at Agincourt. All Days 



1902-1912. 75th M.T. 



Comparing the amplitudes of each wave the result is seen to be 

 the same as in the case of the declination. During maximum sunspot 

 years the seasonal variation is diminished in each wave. The ampli- 

 tude is larger in Ci, C2 and C3 and the same in C4. The phase angles 

 show that the time of occurrence of maximum is on the average for the 

 year earlier in all the terms during the minimum sunspot years; but 

 the effect varies greatly with the season. In the 24 hour term the 

 maximum occurs 52 minutes earlier in winter but 20 minutes later in 

 summer than in the minimum sunspot years. In the 12 hour term 

 the range is from 22 minutes earlier in winter to 4 minutes earlier at 

 the equinox, in the 8 hour term the range is from 19 minutes earlier 

 in winter to 1 minute at the equinox, and in the 6 hour term the range 

 is from 9 minutes earlier in winter to 4 minutes later in summer. 



