a4 A VOYAGE OF DISCOVERY 
for determining the deviation of the compass ; the 
mode of operation was similar to that described some 
time ago, when an experiment of the same kind was 
made: that is, a set of azimuths were taken with 
the ship’s head on every second point of the com- 
pass, and the difference of these azimuths from the 
true variation found on the ice, will, of course, be the 
deviation on these respective points. In this experi- 
ment anewly invented needle by Mr. Jennings was 
used, and as far as we could judge from this trial it 
appeared to answer remarkably well. It differs in its 
construction from the common needle, for instead 
of one bar, or needle, it consists of two placed at 
right angles to one another, so that the magnetic 
north and south falls in a line between the two oppo- 
site arms of it. As the result of this experiment may 
be more easily comprehended by a diagram than by 
words, I have drawn one *, which exhibits at one 
view the whole operation, or rather, as I have just 
said, its results. 
It will be seen from this experiment that the de- 
viation has increased very considerably since it was 
tried before ; this is, however, nothing more than 
what might be expected, or, in fact, it is only what 
we knew, from other circumstances, must happen ; 
for it is very clear, that as the directive power of the 
magnetism of the earth upon the compass decreases 
as we approach the magnetic pole; so will the power 
or rather the effect of the iron in the ship increase. 
Sunday, 25th.— The ice having slackened a 
little during the night, all hands were employed the 
whole day tracking and warping the ships to the 
* See Appendix. 
