1886.] On Local Magnetic Disturbance in Islands, 89 



Sandwich Islands. 





Declination. 



Inclination. 



Total force. 



Observer. 





9° 34' E. 

 8 47 



39° 57' N. 



39 32 



8-512 

 8 '450 



H.M.S. "Chal- 

 lenger," 1875. 







Hilo, Cocoanut Island 



7° 29' E. 

 "8 15 



38° 39' N. 

 37 32 



8-698 

 8-330 



Ditto 





At Honolulu bine magnetism is predominant at the observing 

 station, which, is on the west side of the island, the easterly declina- 

 tion being j° in excess of the normal. The inclination and force are 

 slightly increased. 



A marked difference is seen between the observed declinations at 

 Honolulu and Hilo. At the first-named place the easterly declination 

 observed on the west coast is increased f °, whilst at the latter the 

 easterly declination observed on the east coast is decreased j°. 



The large increase in the observed inclination and force at Hilo 

 above the normal, coupled with the diminished declination, point to a 

 strong development of blue magnetism in that portion of the island 

 visited. 



This concludes our list of islands in which, with the exception of 

 Madeira, blue magnetism appears to predominate. Madeira, however, 

 requires a much more extended series of observations to be made on 

 its shores before any conclusions can be drawn as to the prevalence of 

 either blue or red magnetism. 



Section II. — Islands situated South of the Magnetic Equator. 

 Ascension. 





Declination. 



Inclination. 



Total force. 



Observer. 



Green Mountain .... 



23° 6' W. 

 22 32 

 22 41 



7° 56' S. 

 9 57 

 7 37 



6 133 

 6-217 

 6-100 



H.M.S. "Chal- 

 lenger," 1876. 



The observations at this island are complete at two stations. At 

 Georgetown, on the coast, there is but little local disturbance, but at 

 the Green Mountain Station the observed inclination exceeds the 

 normal in value by 2^°, the force by 012 (nearly), thus pointing to 

 an excess of red magnetism. 



