
488 MR JOHN ALLAN BROUN ON THE BIFILAR MAGNETOMETER, 
39. The following table contains the final results for each bifilar. An exami- 
nation of it will show, that the true temperature coefficient is on an average only 
seven-tenths (5) of that previously obtained from experiments in water of different 
temperatures, and that in some cases the former is only one-half of the latter. 
TABLE XVI.—VALUES OF THE BIFILAR TEMPERATURE COEFFICIENT g AS OBTAINED 
FROM COMPARISONS OF THE DAILY MEANS, AND FROM EXPERIMENTS IN WATER AT 
DIFFERENT TEMPERATURES. 









caeticiee Coefficient ‘ 
Observatory. Magnet.| Period Discussed. “Means Proust k qk = (q). Allee ay. Remarks. 
ae Ments,¢-0 | 1g : 
k 
ea ies Se. Div. Se. Diy. De + lea ep | Soe Se vn 
Makerstoun, .. | 1843-45 1:90 ...  |0:000140| 0:000266| 0:000304| 0:875 
Dec. 1841 ‘ ; ; ; : ; q and q’ for 
{Oct, i843 }| 1283 | 0:05 0000180] 0-000213|o-000290 ova |{ 2 LZ 
Cape of Good Nov. 1843 : : ; ; : : q and q’ for 
Bos { Ost. igde \ 0-587 0:03 |0-00035 | 0:000205) 0:000287| 0-714 { tee 
’ Noy. 1844 : : é ai : ‘ 
CG, { Tune 1846 \ 0:438 0:04 | 0:00022 | 0:000096) 0:000220| 0:484 
St Helena, . 1842-43 1:92 0:06 | 0:000189/ 0:000193) 0:000260, 0-742 {f ae ion 
( April 1842 7 . ; : : d 
a } { Tears \ 1-520 0:05 | 0:000120) 0:000182/ 0:000234| 0-778 
oparton 
; Aug. 1843 ' 
{ Sept. 1848 \ 0-692 0:02 | 0:000229) 0:000158) 0000230] 0:689 
ee No. 3 1842 1°56 0:15 | 0:000135) 0000212) 0-000253) 0:838 
Fe EN. 3) (4 esB-45 217 0:09 | 0000144! 0000312! 0:000347 0-899 
Singapore,. .| ... 1842-45 0-70 0:04 | 0:000195] 0:000137| 0000214} 0-638 
1842 2:53 0:08 | 0:000074| 0:000188) 0:000260| 0-723 
Toronto, . Nov. 1843 : : ; : ; F : 
j sf { ia ie \ 1:36 0:03 | 0:000087/ 0:000118! 0:000234| 0-500 



40. Remaining and Accidental Errors.—I shall notice briefly, in conclusion, 
the other sources of error to which the instrument is liable. 
1st, In suspending the magnet, the wires are apt to receive a twist or kinch; 
as the wire gradually takes the set, the scale readings change, indicating an in- 
crease of horizontal force if the twist has been with the torsion (v), and a dimi- 
nution of force if the twist has been in the opposite direction. An example of 
this is to be seem in the “ Makerstoun Observations,” between June and Septem- 
ber 1841. 
2d, From the wires lying on the szde of the screw threads instead of in the 
hollow. An example of this (if not of the 1s¢) is to be found in the observations 
made at Toronto, when the force appeared to increase ;th of its whole value be- 
tween February 24 and October 9, 1848. 
3d, rom sudden shocks, including those due to concussions of the air by 
thunder- claps and sudden slamming of doors. Examples of both of these were 
observed at the Observatory on the Agustier Mountain in Travancore. 

