OBSERVATIONS OF THE MAGNETIC FORCE. 
293 
“ From these data we have the following values of K' : — 
For ring No. 1. K'= (r 2 +r' 2 )W= log 0‘871 11- 
No. 3. K'= ~ (r 2 +r' 2 )W= log (F59442. 
For the stirrup with weights 5 and 6. K'= — (/ 2 +r 2 )W — log 0 , 80974. 
The values of K (=K' rp^rp ) for each magnet, determined by vibration with 
Dr. Lamont’s rings, were as follows : — • 
Table XXXV. 
With the stirrup. 
Without the stirrup. 
No. 30. 
No. 31. 
No. 30. 
No. 31. 
No. 17. 
No. 20. 
3-2091 
3-2375 
2-1867 b 
2-21 5 4 b 
4-3866 a 
l-9806 b 
3-2220 
3-2477 
2-1867 b 
2-2141 b 
4-3827 b 
l-9804 a 
3-2169 
3-2477 
2-1866 b 
2-2128 b 
4-3880 b 
l-9805 a 
3-2127 
3-2371 
2-1866 b 
2-2145 b 
4-3803 b 
l-9831 b 
3-2212 
3-2437 
3-2163 
3-2427 
2-1867 
2-2142 
4-3844 
1-9812 
a Observed with ring No. 1. b Observed with ring No. 3. 
“ The mean values of K in Table XXV. give the following values of the constant 
log t 2 K, which are compared with the approximate values previously obtained by 
vibration with weights, and by measurement. 
Table XXXVI. 
Vibration. 
Bars. 
Log 
t 2 K. 
With rings. 
With weights. 
With the stirrup 
No. 30 
1-50167 
1-49830 
With the stirrup 
31 
1-50521 
1-50387 
By measurement. 
Without the stirrup . . 
30 
1-33408* 
1-33826 
Without the stirrup . . 
31 
1-33952 
1-33995 
Without the stirrup . . 
17 
1-63621 
1-63872 
Without the stirrup . . 
20 
1-29122 
1-29176 
" Both methods of vibration, with the stirrup and without, were employed at several 
stations, for the sake of comparison, and the horizontal intensity has been deduced 
from the values of m X resulting from each. In the following Table these stations 
* As this value differs materially from the value given by measurement, the bar was again vibrated Sept. 9, 
1845, for the purpose of verification : the resulting value of ir 2 K was however nearly the same, viz. I - 3 344 2. 
MDCCCXLVI. 2 Q 
