TERRESTRIAL MAGNETISM, ETC. 265 



" Supposing such a rock to be under water some 

 " thirty or forty feet and a vessel passing near it, 

 " one can conceive a greater deflection than 30. 

 " Also that there may be ridges of rocks of much 

 " greater extent, and of equal power to the bluff at 

 " Bluff Harbour. In some parts of New Zealand 

 " much larger deflections have been observed." 



Captain Creak also gives me the following 

 extract from Transactions of New Zealand Insti- 

 tute,. 1873, p. 7: 



"North of Port Chalmers the disturbing force 

 " at many stations is very considerable. 



" At Highlay Hill the declination is 2 24' E. ; 

 " in Hawksbury district, at Mount Watkins, it is 

 " 3 W. ; and at Taieri Peak, a few miles to the 

 " North, it is 104 47' E. In Moeraki district, at 

 " trigonometrical station O, it is 26 10' E. ; and at 

 " trigonometrical station P, it is only 50' E. 



" In Kauroo district, at Mount Difficulty, the 

 " declination is i 02' W. ; at trigonometrical sta- 

 " tion L., 13 30' E. ; at trigonometrical station S., 

 22 E.; at Black Cap, 8 54' W. 



" These four stations are included within a radius 



