OP THE MAGNETIC FORCE. 



21 



Increase of scale readings corresponds to decrease of force. Value of one divi- 

 sion of the scale = 0.0000365 parts of the horizontal force, or in the absolute scale 

 equal to 0.0001523. 



Investigation of tfie Eleven Year (a/so called Ten Year) Period, as sliaum in the 

 < '/Hinges of tlie Amplitude of the Solar Diurnal Variation of the Horizontal Force. 

 The variation in the amplitude of the diurnal motion of the horizontal force is 



