2S2 On the Anomaly in the Variation of the 



Sound of Baffin, into which inlet the expedition sailed beyond 81° 

 of west longitude in the parallel of 74"^ and a few minutes. 



It is much to be regretted that the service did not admit an 

 opportunity to be afforded, of making observations on the va- 

 rious magnetic phaenomena, with the excellent instruments sup- 

 plied to the expedition, at this very interesting place ; where a 

 nearer approach was made to one of the magnetic poles than had 

 ever been known before. 



But in the absence of any actual observation on the dip of the 

 needle, this fact of the error of the compasses having increased 

 from local attraction so greatly beyond the amount which had 

 been before observed, is worthv of notice, as affording an indica- 

 tion that the dip had also increased, and not inconsiderably. The 

 greatest which was observed, was 86" 09' ; and after this obser- 

 vation, the ships continued to sail for six days in the direction in 

 which the dip had hitherto been found to increase. 



In concluding this paper, it may be permitted to remark, that 

 it is to the voyages of discovery undertaken during the reign of 

 his present Majesty, that a knowledge of the extent and causes 

 of the errors to which a compass is subject in ships, is to be prin- 

 cipally attributed ; as well as the steps that have been taken to- 

 wards tiie investigation and remedy of the inconvenience they 

 -occasion to practical navigation. 



The care and exertions of Captain Flinders in collecting ob- 

 servations for this purpose, give his opinions and rules a peculiar 

 claim to attentive consideration. No one could have been more 

 fully persuaded than he was, that a rule, founded on the effects 

 experienced in a few ships, would require a far more extensive 

 trial, before it could be depended on for general application. 



To carry this on, therefore, is to follow his useful example, and 

 to effect what he was desirous to have done himself, had his life 

 been spared. 



XLVI. On. the Anomaly in the Variation of the Magnetic Needle 

 us observed on Ship-hoard. By William Scorksby Jiin., 

 Esq. Commiiuicated by the Right Hon. Sir Joseph Banks, 

 Bart. G.C.B. P.R.S.* 



JLhe anomalies discovered in magnetical observations conducted 

 on ship-board, were usually attributed to the imperfection of the 

 azimuth compass, until Captain Flinders, in his modest and en- 

 lightened paper on this subject, published in the Philosophical 



* From Philosophical Transactions of the Royal Society for 181!), Parti. 



Transactions, 



