OF THE llOUlZONTAI, FORCE 



51 



(C.) — Solar-diurnal Variation of thf 

 Scale divisions. 



Horizontal Forcf; April to SF.rTFVRFF., 1S40 To 1845. 



l'i = 0.0000365 parts of the horizontal force. 





April. 



M ay. 



June. 



July. 



A ngui t. 



September 



* ^ — . 

 1*1 



t- N ▼ 



Q-a 



0" 1 2 3 4 5 C 7 8 9 10 11 N. 13 14 15 10 17 la 19 20 21 22 23 24* 

 Philadelphia mean time. 



