1 94 Mr. Flinders orc certain Differences 
differences on the north coast of New Holland will be accounted 
for. I shall leave it to the learned on the subject of magnetism 
to compare the observations here given with those made by 
others in different parts of the earth, and to form from them 
an hypothesis that may embrace the whole of the phenomena : 
the opinion I have ventured to offer is merely the vague con- 
jecture of one who does not profess to understand the subject. 
Some account of the magnetism of Pier Head, upon the east 
coast of New Holland, may not perhaps be thought an unap- 
propriate conclusion to this Paper. I was induced to attend to 
this from the following passage in Hawkesworth, Vol. III. 
p. 126. “ At sun-rise I went ashore,” says Captain Cook, “ and 
“ climbing a considerable hill,” Pier Head, “ I took a view of 
“ the coast and the islands that lie off it, with their bearings, 
“ having an azimuth compass with me for that purpose ; but I 
“ observed that the needle differed very considerably in its 
“ position, even to thirty degrees, in some places more, in 
“ others less ; and once I found it differ from itself no less 
“ than two points in the distance of fourteen feet.* I took up 
“ some of the loose stones that lay upon the ground, and 
“ applied them to the needle, but they produced no effect; 
* In a set of angles taken near the head of Arnhem north bay, on the west side of 
the gulph of Carpentaria, I found the needle of the theodolite had heen drawn 50° from 
its proper direction. The shore consisted o f grains of iron ore caked into a stony 
mass ; and a piece of it, when applied to the needle, drew it 6 or 8 degrees from its 
direction, but it then swung back to its error of 50° where it was stationary. In 
Arnhem south bay a small piece of similar stone drew the needle of the theodolite 
entirely round, yet the bearings taken in this pl.ce did not show any disagreement 
from the variation and herrings taken in the neighbouring places, where the stone did 
not produce any such effect. In most places on shore, where I hsa occasion to take 
angles, it was my practice to try the effect of a piece of the stone upon the theodolite, 
in order to detect the presence of iron ore, as well as on account of my survey. It 
