C 200 3 
Mr. Christie’s Remarks on the repetition of his experiments by 
Lieut. Foster, at Port Bowen, in 1825. 
Having a considerable time previous to the sailing of the late 
North-Western Expedition, in 1824, discovered that peculiar 
magnetic effects were produced in iron by rotation, I was 
desirous of having some of the experiments which I had 
made, repeated under the very interesting circumstances, as 
connected with magnetic phenomena, in which that expedi- 
tion was likely to be placed. Mr. Foster readily offered to 
do this ; and I feel happy in having this opportunity of ack- 
nowledging my obligations to him for the zealous and careful 
manner in which he performed the task which he had so 
kindly undertaken. 
The peculiar effects produced on the magnetic needle by 
the rotation of an iron plate, of which I have given an account 
in a Paper published in the last volume of the Transactions, 
are in this latitude (magnetic) rather minute ; but I expected 
that in the high magnetic latitudes likely to be visited by 
the expedition, these effects being increased in the inverse 
ratio of the cosine of the dip, they would become very con- 
spicuous ; and that some phenomena which here, from their 
extreme minuteness, would escape observation, in those 
latitudes would be easily observable. The result has fully 
answered the expectations which I formed : at Port Bowen, 
where the dip is more than 88°, the phenomena were exhi- 
bited on so striking a scale, and the interest which they 
excited was such, that Mr. Foster devoted much more time 
