on the Variation of the Needle.^ he. in New Holland. 17S 
true bearing of the latter being S, W. Thus the mag- 
netic fluid seemed on this spot to have less influence on the 
needle than on the spot where its power was first observed ; 
and at a short distance from the base of the hill, the needle re- 
gained its natural position. The rocks, when broken, were of 
a dark iron-grey : they did not appear to contain any iron, for 
when tried at the tent, the magnet had no power over them. 
I could not discern any regular stratum of rock, the hill being 
Covered with large detached stones, many of which form figures 
of five and six sides. 
The va,riation of the needle was observed by azimuth to be 
Having again ascended Loadstone Hill, Mr Oxley repeated 
the above experiments with the same results. Several difierent 
stations on the summit ridge were tried, and the needle was' 
variously aifected. The spot where the phenomenon was first 
observed, seemed to have the greatest effect on the needle. A 
common sewing-needle was strongly rubbed with a magnet, and 
balanced on the point of the rock, when it was mucK agitated, 
and the point flew round from the north to the south. The 
needle of the circumferentor, taken out of the box, was affect- 
ed in a similar manner, only that when balanced on the rock, 
the fluid did not possess sufficient power to turn the point more 
than one point of the circle instead of quite round, as when 
balanced ^n the compasS-box. A compound magnet was laid 
on the rock, and applied to it in different ways ; but it did not 
seem in any manner affected by the power which had so sur- 
prised us with its effect on the compass.” The observations 
made here placed us in Lat. 31° 13' S., Long. 148° 41' 30" E., 
and I estimate the mean variatibn to be about 7^° Easterly. 
We found that no reliance could be placed on bearings taken 
with the compass on heights in this vicinity, and I am fearful 
that the bearings taken from Mount Exmouth will require 
verification, a difference of 4° being observed in some, when 
compared with other bearings, which could not be supposed to 
be affected by the magnetic fluid.” 
M 2 ■ 
3 
