48 



DISCUSSION OF THE VERTICAL COMPONENT 



(C). SoLAR-DltTKNAL VARIATION OF THE VERTICAL FORCE, APRIL TO SEPTEMBER, 1841 TO 1845. 



(Expressed in scale divisions.) 

 11 = 0.000033 parts of the force. 



April. 



May. 



June. 



July. 



August. 



September. 



I 



I 



0" 2 



6 8 10 g 14 16 18 20 22 24" 



Philadelphia mean time. 



