Mr Christie’s Observations 
Helena, and during the voyage home, on board H. M. S. Con- 
queror, as offering results obtained under different dips of the 
needle. 
The first experiments which he details, are some on long iron 
bars ; and in these, in a great variety of positions of the bars, he 
marks the situations of the compass, where its respective ends 
appeared to be attracted by the bar, and also the points where 
the compass appeared not to be influenced, which he calls 
44 neutral” points. These were made at the several dips of the 
needle, 12° S. 23° N. 61° N. As, with a little attention, it is 
immediately seen that, in all these, when the compass was at the 
44 neutral” points, the centre of the bar was in the plane of the 
magnetic equator of the compass, and therefore, according to 
what I have stated, ought not to influence the horizontal needle, 
I shall not dwell on them, but proceed to some which were made 
f with an iron ring in different positions. 
44 The following experiments were made in latitude 32° N. 
longitude 38° W., with an iron ring 10.2 inches in diameter, and 
5.5 inches thick, with the ring vertical ; the letters on the ring 
shew which pole of the compass was attracted ; and the letters in 
the centre of the ring shew which plane the compass was placed 
against. 
64 From vertical to horizontal southerly, very slight changes; 
1:1 but with an inclination of 
45° top to the northward, 
south face attracted all 
round the north end of the 
needle, and the north face 
attracted the south end of the needle all round. Edges were 
nearly neutral. 
N 
3—^ “ Inclined 55° north- 
/' ward, north side attracted 
j g j nearly all south, and south 
\ f side nearly all north. Bot- 
tom faintly inclined to 
attract south 
® The left hand figure has been altered, as in Mr Lecount’s it is ?iewed in a 
contr ary manner to the others. 
