16 



DISCUSSION OF THE A^ERTICAL FORCE. 







forrectioa. 



A„pu„l nu-ans 



1 Fruni !l m..Dlhs. 



Conection- 



A,u,u,.l n,ou„» 





701 



+3 



704 



Noon 



6S2 



+ 8 



690 





ti96 



+3 



099 



14 



6S1 



+ B 



6S7 



4 



(JitV 



+5 



702 



16 



683 



+ ^ 



690 



6 



By? 



+6 



703 



18 



689 



+7 



696 



8 



G90 



+e 



696 



20 



697 



+5 



702 



10 



686 



+7 



693 



22 



700 



+5 



705 



The normals for 1843-44 at the even hours are complete, at the odd hours they 

 extend only o^•er nine months. To refer the latter to twelve months, the difference 

 between the means of the same nine months and the annual mean at the even hours 

 was made out and applied as a correction to the means of the odd hours ; the cor- 

 rection thus applied is the mean difference as deduced from the preceding and fol- 

 lowing even hour. 





Means of 9 months. 



Correction. 



Annual means. 





Means of 9 mouths. 



Correction. 



Annual mean.. 



1" 



749 



—11 



738 



13" 



728 



—14 



714 



3 



746 



—10 



736 



15 



726 



—16 



720 



5 



746 



—11 



735 



17 



744 



—16 



728 



7 



744 



—11 



733 



19 



752 



—15 



737 



9 



737 



—12 



7l!5 



21 



751 



—14 



737 



11 



730 



—13 



717 



23 



754 



—13 



741 



Table VI. — Annual Means of the Bi-hourly and Hourly Normal Values of tue Regular 



Solar-Diurnal Variation of the Vertical Force. 



The numbers are expressed in scale divisions, increasing values indicate decrea.se of force. The minutes at the 



head of each column are to be added to the hour given in the first column. Each year commences with the 



month of July. The time is local Philadelphia time counted from midnight to midnight. 



Hour. 



1841^2. 



1842-43. 



1843-44. 



1844-45. 





+ni™ 



-^20^" 



+23J'" 



4-23i." 



A.M. 



650 



704 



740 



765 



1 " 







738 



761 



2 " 



643 



699 



735 



759 



3 « 







736 



760 



4 " 



643 



702 



737 



761 



5 « 







735 



761 



6 « 



640 



703 



734 



761 



7 " 







733 



759 



8 « 



634 



696 



727 



752 



9 " 







725 



751 



10 " 



632 



693 



722 



749" 



11 " 







717 



747 



12 P. M. 



633 



690 



717 



745 



13 " 







714 



742 



14 •« 



631 



687 



718 



741 



15 " 







720 



746 



16 " 



636 



690 



724 



753 



17 " 







728 



758 



18 " 



647 



696 



732 



762 



19 « 







737 



764 



20 " 



654 



702 



738 



763 



21 " 







737 



761 



22 " 



652 



705 



738 



761 



23 " 







741 



764 



Means 



641 j 697 1 730 756 



