DISCUSSION OP THE VERTICAL FORCE. 



15 



Table IY. 



— Continued. 



Hourly Normals or 



THE Vertical Component in 1845. 



~^ 







The observations are made 23i" 



after the full hours. 









1845. 



0" 



1 



2 



3 



4 



5 



6 



7 



8 



9 



10 



11" 



January 



754 



747 



747 



752 



752 



757 



763 



767 



760 



758 



753 



752 



February 



760 



756 



752 



757 



759 



760 



763 



764 



756 



756 



752 



749 



March 



749 



741 



736 



742 



746 



748 



749 



746 



736 



733 



732 



729 



April 



732 



727 



728 



729 



728 



727 



725 



721 



718 



715 



717 



717 



May 



720 



718 



717 



719 



716 



715 



713 



709 



705 



702 



701 



699 



June 



733 



731 



729 



730 



729 



728 



726 



722 



717 



715 



715 



711 



1845. 1 Noon. 



13 



14 



15 



16 



17 



18 



19 



20 



21 



22 



23" 



January 



751 



748 



749 



742 



753 



760 



756 



753 



749 



746 



747 



754 



February 



747 



741 



740 



744 



753 



759 



761 



761 



758 



753 



752 



756 



March 



729 



729 



713 



734 



740 



747 



751 



746 



741 



740 



739 



743 



April 



716 



713 



717 



720 



724 



724 



732 



737 



736 



729 



726 



727 



May 



6W7 



696 



701 



698 



702 



705 



710 



720 



718 



717 



718 



719 



June 



711 



711 



713 



714 



713 



714 



722 



730 



735 



731 



731 



733 



Table V.. — Number of 



BSBRVATIONS AND LARGER DISTURBANCES IN EACH 



Month. 





1811. 



1842. 



1843. 



1844. 



1845. 



Ots. 



Bis. 



Obs Bis. 



Obs. 



Dis. 



Obs. 



Dis. 



Obs. 



Dis. 



January . . . 







300 



76 



26 



5 



646 



81 



648 



17 



February 









288 



49 



284 



86 



24 



3 



600 



33 



576 



5 



Mareh . 









321 



64 



322 



36 



27 



12 



624 



106 



624 



68 



April . 









304 



46 



306 



51 



300 



00 



624 



83 



624 



24 



May 









223 



16 



293 



47 



324 



36 



648 



8 ■ 



648 



28 



June . 









310 



91 



310 



87 



312 



16 



bOO 



52 



600 



9 



July . 









323 



64 



305 



24 



312 



4 



648 



45 







August 









304 



21 



318 



34 



324 



10 



648 



94 







September 







307 



40 



303 



57 



312 



20 



600 



14 







October . 







308 



28 



310 



12 



624 



25 



648 



20 







November 







312 



37 



312 



13 



624 



79 



624 



10 







DecembfiK 







323 



84 



319 



15 



624 



65 



624 



47 





151 



Sum • • • 3323 540 



3682 1 488 



3833 



325 



7534 



593 



3720 



Ratio ... 



1 dis. in 6.2 obs. 



1 dis. in 7.5 obs. 



1 dis. in 11.8 obs. 



1 dis. in 12.7 obs. 



1 dis. in 24. 6 obs. 



Total number of observations used, 22092 



• " " larger disturbances, 2097 



Ratio of disturbances to observations, 1 to 10.5 



Investigation of the eleven year {also called ten year) period in the inequality of the 

 amjMtude of the D'mrnal Variation of the Vertical Force. — The preceding monthly 

 means of the bi-hourly and hourly normals were rearranged in four groups of one 

 year each, necessarily omitting the first five months ; the annual means have for 

 their mean epoch, January, as the montlily means were arranged from July to July. 



The means for the year 1842-43 depend on nine months only, to refer them to 

 the mean of twelve months, the differences for every observing hour, between the 

 same nine months and twelve months for the preceding and following year, Avere 

 made out and the mean correction, giving the weight two to the following year, as 

 indicated by the readings taken at the hour 14, was applied to the values of 1842-43. 



