1 18 Capt. Sabine on irregularities observed 
distant, that the space occupied in warping the ship round 
may not subtend any sensible parallax. The direction of the 
ship’s head should be noted by the compass by which the 
bearings are taken. A short time must be allowed to elapse 
after the ship is steady on any point, to ensure the traversing 
of the cards : this is particularly necessary in high latitudes 
when the compasses move very sluggishly. And lastly, the 
observations should be repeated. 
It will be observed by the above results, in the Isabella 
and Alexander, that the points of no error were not coin- 
cident in either ship with those of the magnetic meridian ; 
in the Alexander especially, they were more nearly at right 
angles to it. That this ship should have differed so mate- 
rially from all the instances on record, may be attributed to 
her compass being so near the level of the deck, and there- 
fore being more affected by the influence of a considerable 
quantity of iron articles (such as ice anchors, ice saws, See . ) 
which were carried on the after part of the deck for conve- 
nience in use, than it would have been, had it been raised 
higher. This was proved by placing a compass on a plank 
elevated for experiment in front of the companion, to the same 
height as in the Isabella, namely, nine or ten feet. The 
points of no error were found, in this position, to be about 
north and south, and the amount of error at eight points, 
nearly twenty degrees ; the same as in the Isabella : the 
greatest error at the same time, by the Alexander’s standard 
compass, viz. the one nearer the decks, being 8° 20' at N. N. E. 
The dip was 84° 09'. 
The propriety of Captain Flinders’s recommendation, to 
determine the points of no error in a fixed compass by actual 
