50 
CAPTAIN SABINE ON THE DIP OF THE 
Exp. V. 
Exp. VI. 
Exp. VIE 
August 16th. 3 to 5 P.M. Therm. 66°. 
Time of Vib". 
Marked end a N. Pole 54 s .O 
Marked end a S. Pole 53 .6 
f W. below ; 53° 07'.0 
IW. above ; 87 1 1 .2 
fW. below; 58 55.2 
LW. above ; 84 37 .6 
69°42'.0 
August 20th. Noon to 2 P.M. Therm. 68°. 
Marked end a S. Pole 53 s .6 
Marked end a N. Pole 52 .8 
fW. below; 57°28'.7 
LW. above ; 8 7 33 .4 
fW. below ; 52 48 .3 
LW. above; 88 19.8 
69 58.8 
August 20th. 4 to 5 P.M. Therm. 67°. 
Marked end a N. Pole 
Marked end a S. Pole 
f W. below ; 52° 06'.0 
IW. above; 89 51 .0 
LW. below ; 57 12 .0 
LW. above ; 86 13 .0 
Mean . 
Dip 69 40.5 
69 47.4 
With the same general apparatus I employed also two other needles : one a 
flat needle with a cross of wires attached to the axis, two in the longitudinal 
direction of the needle, and two at right angles to it. By means of small 
weights sliding on these wires, the axis could be brought very nearly, if not 
exactly, to coincide with the centre of gravity. The same number of obser- 
vations were made with this needle, and in the same general manner as in the 
experiments numbered I, II, and III. The following is the result obtained. 
August 20th. 2 to 4 P.M. Therm. 69°. 
Exp. VIII. 
f Marked end a N. Pole 
\ Marked end a S. Pole 
24 Readings 
24 Readings 
69°34 , .25 
69 42 .35 
69°38 , .3 
The other needle was on a plan proposed some time ago by Mr. Dollond. 
The two ends of this needle are conical ; the bases of the cones occupy two 
sides of a cube, which forms the middle of the needle ; the other four sides 
being perforated for the purpose of receiving the axis in every direction. These 
sides are numbered for distinction 0, 1, 2, 3 ; 0 being opposite to 2, and 1 to 3. 
The axis is passed through the perforation until a shoulder on the one arm of 
the axis blocks against one of the sides of the cube, 0 for example : a nut is 
then screwed on the other arm of the axis against the side 2, until the axis is 
tightened in its place, care being taken that the same parts of the axis coincide 
