140 ABSTRACTS FOR THE HORIZONTAL FORCE. 
TABLE VIII.—The Monthly Means of the Scale Readings of the Bifilar Magnetometer, as Corrected in this 
Volume, for 20", 23, 22, and 54, 
Month. 204, fs : 5h, 
1841. Se. Div. Se. Div. Se. Div. 
July 472-04 486-96 500-35 
7 August 528-00 540-45 550-06 
September 
544-36 554-78 558'86) 
{ee 575-74 593-05 f 
558-26 564-55 585-93 
485°32 496-05 507719 
495°31 517°36 509°86 
489-60 506-20 508-46 
November 502-48 509-41 510-47 
October | 
1842. 
January 
February 
March 
April 
May 
June 
July 
August 
September 
October 
November 
December 
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 g, the co-efficient for the temperature correction, having been obtained from I 
a comparison of the Daily Observations in 1844, 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. 
