ITS ERRORS AND CORRECTIONS, ETC. 477 
Whence, since 
k = 0:000180, 
qk = [q] = 0:0002138. 
The value of g determined by hot water experiments was found for the magnet R, 
g = 0:000258 at the temperature of 48° 
q = 0000804 r 77° 
the value of g varying apparently with the temperature, as occurs with some 
bars. The value of g at the mean temperature of the bar for the months in 
Table IV. is 
gq = 0:000290 at the mean temperature of 63°6 ; 
whence [q] = 0°734 q. 
The same value of g' (=1-:18) has been employed by me (for the discussions given 
in another paper) in the corrections for all temperatures. 
24. November 1843 to September 1844.—New adjustment of magnet R, 
k = 0:00035. 
TABLE V.—SUMS OF SUCCESSIVE DIFFERENCES OF DAILY MEANS. 





Month. ZAt. ZAR. qi Month. ZAt. ZAR. 
arantunk rae Se. div. &é Se. div. 
1843. Noy. 27°74 11°83 0:43 1844. May. 24°87 17:01 
Dec. 32:24 21-01 0°65 June. 25°55 12-11 
1844. Jan. 33°75 17:12 0°51 July. 24-41 14:15 
Feb. 83'54 27:07 0°81 ‘Aug, 22°71 15:07 
March. 28°84 18°42 0:64 Sept. 25°74 13°54 
April. 31:12 14°89 0°48 Oct. New | Magnet | C. 


The resulting value, the mean temperature of the bar being 67°, is 
ZAR 182:22 } 
Shs ee ST 0°587 sc. div., 
with a probable error of 0°03 sc. div. Whence, 
[q] = 0:000205 ; 
and since, q = 0:000287 at the temperature of 67° 
[q] = 0714 ¢. 
As it is quite possible that the temperature coefficient for the same bar might be 
different for / = 0:00018 and & = 0-00035, the coefficient 9’ = 0-587 sc. div., has 
been employed by me from November 1848 to September 1844. It is rendered 
probable by the near agreement of the values of [q] in these two adjustments, 
that the difference from the value of g is not due to error of the coefficient £. 
25. November 1844 to June 1846.—Magnet C,, new adjustment, 
k = 0:00022. 
