140 



Abstracts foe the Horizontal Force. 



TABLE VIII. — The Monthly Means of the Scale Readings of the Bifilar Magnetometer, as Corrected in this 



Volume, for 201^, 2S\ 2^, and 5^^. 



Month. 



20i>. 



23h. 



2''. 



5i>. 



1841. 



Sc. Div. 



Sc. Div. 



Sc. Div. 



Se. Div. 



July 



August 



472-04 



466-30 



486-96 



500-35 



528-00 



528-28 



540-45 



550-06 



September<' 

 October J 



f54-t-36 

 (56212 

 558-26 



540-08 

 554-27 

 552-32 



554-78 

 575-74 

 564-55 



558-86) 

 593-05/ 

 585-93 



f485-32 

 (495-31 

 489-60 



484-42 

 495-14 

 489-78 



496-05 

 517-36 

 506-20 



507-191 

 509-86] 

 508-46 



November 



502-48 



499-33 



509-41 



510-47 



1842. 











January 



516-45 



513-28 



522-98 



522-81 



February 



517-62 



514-61 



523-82 



528-07 



March 



518-40 



513-20 



525-92 



532-65 



April 



510-58 



507-32 



524-48 



537-73 



May 



524-78 



520-31 



533-78 



542-47 



June 



527-29 



523-56 



539-14 



549-57 



July 



521-85 



521-21 



542-29 



549-90 



August 



528-38 



524-02 



542-77 



550-14 



September 



531-31 



523-78 



540-32 



545-03 



October 



534-60 



527-32 



540-12 



543-03 



November 



536-26 



533-85 



542-97 



544-06 



December 



544-33 



542-69 



547-79 



547-74 



As there was an adjustment of the Bifilar Magnetometer between July and August, and between September 

 and October 1841, the observations in July 1841 are not comparable with the others; August and September 1841 

 are comparable with each other only. 



In September 1841 and October 1841, the torsion circle was moved 50', in order to make the middle of the 

 scale nearly the mean reading, from which it had moved considerably in each case after the previous adjustment : 

 there seems little doubt that this rapid change had some connection with torsion in the silver wires. It is very 

 probable that this source of error still shews itself in November 1841. 



The observations from September 7*^ 20'* till the end of September have been reduced to the value of v in 

 August and beginning of September ; those from October 6*^ to October 20*^ have been reduced to the value of v 

 after. In each case, the means of reduced and unreduced portions of the month have been printed in small type, 

 the means in large type being the means for the month. 



A new and preferable value of q, the co-efficient for the temperature correction, having been obtained from 

 a comparison of the Daily Observations in 1 844, the following Table has been formed ; it was thought well, 

 however, to give the means as corrected in this Volume, for the purposes of comparison. 



