ADDENDUM. 
lxxi 
Table 17. Results of Observations for the Absolute Horizontal Intensity made 
with Circle Magnetometers in 1846 and 1847. 
6-in. Circle. 
6-in. Circle. 
9-in. Circle. 
9-in. Circle. 
9-in. Circle. 
9-in. Circle. 
ome 
og x 1B, Q. 
9-1603750 |+0-016708 | —0-003344 
9-1564802 |—0-005080 | + 0-002391 
9-1810278 |+0-000655 | —0-000600 
9-1731457 |+0-000172 |—0-000526 
9-1732756 |+40-000899 | —0-000729 
9-0952645 |—0-002388 |+0-000387 
Log m X. 
0-2146240 
0-2107538 
0-2420858 
0-2344397 
0-2310949 
0-1518040 
Result. X at the 
Mean 
x Bifilar | Bifilar 
Fa Reading. | for 1845. 
3-3661 | 568-7 | 3-3528 
3-3662 | 560-9 | 3.3564 
3-3926 | 574-8 | 3-3764 
3-3935 | 576-7 | 3-3765 
3:3799 | 545-0 | 3-3774 
3-3750 | 524-9 | 3-3816 
The resulting values of X, by Professor Fores’ instrument, differ considerably 
from those by Sir THomAs BrisBANz’s, while the latter agree much better with the 
results obtained with the 15-inch bars, see Table 12. 
Maxerstoun, March 1849. 
