amount of the dip of the magnetic needle , in London, &c. 11 
Abstract of ten experiments with Meyer's needle. 
o / o / 
Exp. i. Aug. 3. -j 
; Sphere 8 screwed 
half up. 
7 f Marked end of the 
j l Needle being a. 
MN. Pole ; F — 3 J 08,2 and f ~+ 922,3] 
S l S. Pole ; G 12:29 41,3 g — + 6 17,4 f 
O / 
>70 03, 3 N. 
Exp. 2. Aug. 6. | 
j Sphere 1 close to 
the Needle. 
H — 
7 5 N. Pole ; F =49 1 \,j 
j \ S. Pole; G=46 58,7 
f — — 22 22 7 
g =—20 09 ] 
• 7° 04, 7 
Exp. 3. Aug. 6. < 
i Sphere 8 nearly as in 
[ the 1st Experiment. 
H — 
1 f N. Pole ; F =30 36,8 
| ( S. Pole ; G— 28 47,7 
/=+ 10 08,3 7 
g = + 7 4 6 > 6 J 
> 7 ° 4 
Exp. 4. Aug. 1 1. 1 
j Sphere 3 close to 
l the Needle. 
H — 
7 j N. Pole; F —45 5 3 
f | S. Pole ; GZ241 50,7 
f 4 49 > 1 ] 
g — 11 28,7 j 
■ 70 00, 1 
Exp. 5. Aug. 13. 1 
j Sphere 7 close to 
^ the Needle. 
H — 
7 j N. Pole ; F =27 24,3 
j { S. Pole; G=:24 14,2 
/ = + H ° 7 ’ 2 7 
g =+13 21,7 j 
• 70 05, 9 
Exp. 6. Aug. 13. | 
\ Sphere 6 close to 
[ the Needle. 
H — 
7 j N. Pole ; F 21:30 36,2 
j { S. Pole; G—27 12,6 
/ = + 10 17,2 ] 
g- 2+9 > 5’3 j 
7 ° ° 3 » 5 
Exp. 7. Aug. 15. < 
[ Sphere 5 close to 
[ the Needle. 
H — 
MN. Pole ; F — 32 00,2 
j ( S. Pole; G“ 2 8 57,4 
J =+ 8 ° 3>4 } 
g=+ 7 4°’9 i 
• 7 ° ° 5 > 2 
Exp. 8. Aug. 15. < 
j No Sphere ; weight 
[_ of the screw close. 
H — 
1 f N. Pole ; F =24 14 
j { S. Pole; G2=22 17,5 
/ = + >7 34 > 1 7 
g =+15 34 > 8 i 
■ 70 00, 9 
Exp. 9. Aug. 20. | 
) Sphere 1 close to 
[ the Needle. 
H — 
MN. Pole ; F —48 24,7 
j 1 S. Pole ; G=44 57,1 
/ 22— 1925 7 
g=—'7 19 i 
> 70 00, 3 
Exp. 10. Aug. 20. • 
C Sphere 7 close to 
[ the Needle 
}{ — 
7 t N. Pole ; F = 24 27,6 
5 7 S. Pole; G”22 04 
Z = +17 38,5 7 
g 221+1522 j 
• 70 03, 8 
Dip in London, 
August 1821 — 
70 02,91 N. 
Note. The screw on which the spheres traversed was made, in the first instance, 
half an inch in length, but was shortened one half after the third experiment ; being 
found still longer than necessary, it was again shortened after the eighth experi- 
ment, until its length just equalled the diameter of the largest sphere. 
Being desirous to confirm the correctness of the result 
obtained with Meyer's needle, I made the following expe- 
riments' for the purpose of deducing at least an approxima- 
tion of the dip by a method suggested, I believe, originally 
by Laplace, of observing the times in which a certain num- 
ber of oscillations are made by a dipping needle, in the mag- 
netic meridian, and in the plane perpendicular to it. 
