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V. Observations for determining the dip of the magnetic needle. 
Dip of the magnetic needle observed at Woolwich , and at 
different stations within the Arctic Circle. 
1 n the following Table, is given a general abstract of the 
dip of the magnetic needle; and of the magnetic intensity, 
observed at different stations within the Arctic Circle, in the 
years 1824-25 ; and of those at Woolwich, both prior, and 
subsequent to the voyage. 
The instruments employed in these observations; were 
those by Jones, and Dollond, already described in the Ap- 
pendix to the two preceding voyages of discovery ; but on 
this occasion, other needles were added, the whole being 
numbered as follows : 
No. 1. A rectangular needle, 7^ inches in length, constructed 
by Jones on Meyer’s principle, having a light cy- 
lindrical arm at right angles to its axis, for screwing 
on a small brass sphere. 
2 . The same needle, with a sphere somewhat larger. 
3 . The same needle, with a still larger sphere. 
4. A plain rectangular needle of the same length as the 
above. 
5. A needle similar to No. 4, but used only for the in- 
tensity. 
6 . A conical needle, by Dollond, ni inches in length, 
having a moveable axis, for shifting into four dif- 
ferent positions ; used with the instrument of his 
construction. 
