418 PROCEEDINGS OF SECTION E, 



The distance between the largest east and largest west 

 repulsion would be greater. 



In a wooden ship or composite vessel like the Penguin, 

 the compasses would act as usual after leaving the shoal. 

 Whether induction would take place or not in an iron vessel 

 is a matter yet to be ascertained. At present there does not 

 seem to be any evidence that there is any danger to naviga- 

 tion, except that a vessel would be set out of her course if 

 steering by compass when passing over it, more or less, 

 according as to whether she cut across it at the narrowest 

 part or obliquely. 



The focus is in lat. 20° 32' 35'' S., long. 117" 13' 2" E. 

 From it Bezout Island summit bears S. 78° 49' W., distant 

 2-17 miles. 



The greatest range in the deflection of the compass card 

 was 82°, after applying the deviation for the apparent posi- 

 tion of the ship's head : the actual range, 86°. 



The greatest inclination or dip, 81° 10'. 



The greatest intensity or total force found was 18'808 

 (British units), or nearly double the intensity which, in this 

 locality, is due to the earth considered as a magnet. This is 

 the greatest known intensity generated by an invisible cause. 

 The largest recorded intensity in the world, due to the earth 

 considered as a magnet is 15-2 B.U., near the south 

 magnetic pole. 



The statement made by Captain Creak, F.R.S., the 

 Superintendent of Compasses, that the north point of the 

 needle is always repelled from the disturbing cause in the 

 Southern Magnetic Hemisphere is fully confirmed by this 

 investigation. 



H.M.S. " Penguin" Admiralty Gulf, 20th June, 1891. 



Note. — Commander Moore, in forwarding the above to 

 the Admiral, slates that " It seems probable that Captain 

 Cook came across an area of disturbance like this Avhen near 

 Magnetic Island, off the coast of Queensland." 



