312 APPENDIX. 
No. IV.—A DIAGRAM, 
Exhibiting a Series of Azimuths taken on every second point of the Compass, 
for the purpose of determining the Deviation on board His Majesty’s ship — | 
Hecla, July 24th, 1819, in latitude 73° 00’ N. long. 60° 26’ W. 
81°20/25" 
39/35" 
, 
8/°05. 
\66°11'19" 66 
pLG OTo96 uF UGSoST Ama eran - 
\ES SE096 1 1/G9 086 
In the above diagram, the letters contained in the outer circle represent the direction of the 
ship’s head when the azimuths were taken ; the circle next to it shews the amount of the yari- 
ation observed on each direction of the ship’s head; the figures on the left side * of the rhumb- 
lines being taken by one of Kater’s azimuth compasses, and those on the right side of the same 
lines, by a card of Mr. Jennings (placed on the stand of Walker’s azimuth compass), having 
two magnetic needles placed at right angles to one another. The figures on the left side of the 
xhumb-lines in the next circle, are the mean of the two observations, which is taken as being 
likely the nearest approximation to the truth: the figures on the right side of the rhumb-lines in 
this circle, shew the difference between the mean variation observed on each direction of the ship’s 
head, and the true variation, as observed on the ice, which, by the mean of twenty-six‘azimuths, 
was found to be 82° W. ‘The figures in the inner circle are the sum of the two opposite points, 
which is presumed to be the true variation on these points; finally, the mean of all the obsery- 
ations, when summoned up, were 80° 48! 39” 37°” W. 
* As this term may, in the present instance, be misunderstood, it is necessary to observe, that 
the figures on the left side of the rhumb-line, North, are 81°43’ 10’, and on the right side 
#0° 57’ 40”, and so on. 
