Tlie Magnetic Shoal near Bezoat Island. 67 



meridian, at an angle of 06°, in the neighbourhood of the 

 focus. This angle coincides with the angle of maximum 

 easterly- re])ulsion. 



A vessel passing in a straight line across the magnetic 

 shoal at the focus, on a north-westerly course, would find 

 the north-seeking end of the needle behave in the following 

 manner : — When about 1 mile from the focus, a slight 

 <listurbance would be observed, the north-seeking end of the 

 needle being repelled to the east ; but this disturbance 

 would not amount to more than half a point, until she had 

 run to within 500 yards of the focus ; the needle would 

 then be more and more repelled, until 300 feet from the 

 tocus, when it would be deflected as much as 56° from the 

 true north. It would then quickl}^ resume its correct 

 position, and over the focus — for a hardly appreciable 

 distance, .say 8 feet — would point true to tlie north. After 

 ]:)assing the focus, it would be repelled to the west, and at 

 200 feet from it, would be deflected as much as 26°. It 

 would now begin to return again to its proper position, and 

 at 600 yards from the focus on the north-west side, would 

 not deviate from the normal more than half a point. At 

 one mile from the focus, all signs of disturbance would 

 <lisappear. Crossing the shoal rectangulai'ly, elsewhere than 

 at the focus, similar, but less powerful repulsion would be 

 observed. The distance between the largest east and largest 

 west repulsion would be greater. 



In a wooden ship or composite vessel like the " Penguin," 

 the compa.sses would act as usual after leaving the shoal. 

 Whether or not induction would take place in an iron 

 vessel, is a matter yet to be ascertained. At present there 

 is no evidence of danger to navigation, except that a vessel 

 steering by compass across the shoal would be set out of 

 her course, more or less, according as to whether she cut 

 across it at the narrowest part, or obliquely. 



The focus is in latitude 20° 32' 35" S., longitude 117° 13' 2" 

 E. from it. Bezout Island summit bears S. 78° 49' W., 

 distance 2- 17 miles. The greatest range in deflection was 

 82°, after a])plying the deviation for the apparent position of 

 the ship's head ; the actual traverse of the card 86°. The 

 greatest inclination or dip of the needle was 81° 10'. The 

 greatest intensity or total force found was 18'808 (British 

 units), or nearly double the intensity, which, in this locality, 



