66 OBSERVATION OF ABSOLUTE HorizonTaL INTENSITY, Marcu 26. 1842. 
OBSERVATIONS OF DEFLECTION. Biritar Mae- OBSERVATIONS OF VIBRATION. BIFILAR MAGNETOMETER, 
NETOMETER. 
cosa cana Roving 60 60 |) Time of Ther- 
Rae Sa el of Mean Read- |Thermo-} _ 8. End Vibra- 8. End Vibra- Obser- Read- mome- 
Distance. | p,q, |Suspended Deflection.|| ings, | meter. | Moving W. | tions. Moving BE. tions. vation. ings. | ter. 
Magnet. 
Ft. Se. Div. Se. Div. Se. Div. 7 hom 5s. m & hm 8. m. 48. h. m. s. | Se. Div. < 
5.25 W W. 36-61 212.37 153-9 | 54:0 | 3 16 33-0 3 16 49-0 3 18 30/161-5 |56-0 
“| E. | 461-34 150-3 | 54-4 21 35-4 21 51-0 21 0O| 166-6, | 56-0 
3-50 W. E. 308-13 60-57 156-2 | 55-2 26 37-3 26 53-0 23 30) 166-8 | 56-0 
“| W. | 186-98 149-2 | 54-8 31 39-4|15 6-4 31 55-3)15 6-3 26 0] 166-0 | 56-0 
850 E E. 307-09 59-87 151-2 | 55-8 36 41-6|15 6-2 36 57-4|15 6-4 28 30] 164-5 |55-9 
‘ W. | 187-35 152:3 | 56-0 41 43-6) 15 6-3 41 59-4/|15 6-4 31 0} 162-3 | 55-9 
5.25 E W. 35-45 211-61 151-3 | 56-2 46 45-9) 15 6-5 47 1-6|15 63 33 30] 162-2 | 55-8 
: E. | 458-68 153-1 | 56-3 36 0/ 159-5 | 55-7 
38 30] 160-0 | 55-7 
41 0| 160-4 | 55-6 
43 30) 158-7 | 55-5 
46 0| 156-4 | 55-4 
rv =5-25 feet. Mean deflection 211-99 Se. Div. u =2° 22’ 14”.7 
Ma BGO) wae) Peceecadveetvveats (A020) Gercocioce u’ =0° 40’ 24”.4 
Observed mean time of one vibration, T’ = 15%-1058. 
7 div. 
Mean Bifilar, {Then \ during deflections, { uae \ Reading corrected, 523-8*"- 
: Reading " 5 : 162.1% : raat 
Mean Bifilar, { Theeatt during vibrations, { 55°-8 \ Reading corrected, 534-8 
Difference of Bifilar readings during deflections and vibrations corrected = Asam =11-0 Se. div. 
= -00137 in parts of force. 
2 =0-000994. (See Introduction for value of = March 3. 1842.) 
at commencement a c a =100 
Semi are 1s eaninaten \ of vibrations, ea 6° 
(eases a =1-25 feet, 
Deflecting bar, «Breadth, b =0-0719 feet, 
Weight, W = 6216-7 grains. 
From the formulz below there has been obtained X = 2-9662. 
24 p2 
Moment of inertia K = “ as W. 
ra +e Ht oa) = T, time of vibration corrected. 
2F 16 
aK AX Am - . 
~ (: + x tm ) =m X at the period of deflections. 
(1 Zo ay : > tanw—r tan m 
F (8-7) ~ XxX" 
The hours of the deflection observations have not been registered. 
The ares of vibration were not registered. The above have been estimated from a remembrance that Mr. 
Russell used rather large arcs of vibration, and from other considerations. The times of vibration were obtained 
from the clock in the observatory ; the rate is not registered, but it was generally very small. 
The notation and formule above are those used in the Report of the Royal Society. 
