Magnetic Observations. ] SUBANTARCTIC ISLANDS OP NEW ZEALAND. 



787 



Between September, 1840, and April, 1841. 



On Shore at 



Lat. S. 



Long. E. 



Number of Ob- 

 servations. 



Total Force. 



British Units. C.G.S Unit. 



Auckland Island . . 

 Campbell Island . . 



50 33 

 52 34 



166 19 

 169 10 



20 

 10 



13-79 



14-08 



0-63577 

 0-64914 



Bet 



ween I3th November, 1840, 



and April, 1841. 





On Shore at Lat. S. 



Long. E. 



Number of Ob- 

 servations. 



Magnetic 

 Dip S. 



Deduced Value of 

 H., C.G.S. Unit. 



Auckland Island . . 

 Campbell Island . . 



50 33 

 52 34 



166 19 

 169 10 



3 



8 



73 24 



74 20 



0-18586 

 0-18617 



Average Annual Change of Declination over the Sixty-seven Years, 1840-1907. 



At Terror Cove, Auckland Island . . . . . . . . . . + 0'-34 



At Head of Perseverance Inlet, Station C, Campbell Island . . . . + 2'-87 



Mean . . . . . . . . . . + l'-60 



Average Annual Change of Horizontal Force and Dip over the Sixty-seven Years, 1840-1907. 



H. Dip. 



Entrance to Port Ross, Auckland Island . . . . — 12-9y -f 0'-58 



At Head of Perseverance Inlet, Campbell Island . . — 26-8-y + 0'-36 



Means 



19-8y 



+ 0'-47 



At the entrance to Port Ross the 1840-41 observations appear, from the position 

 assigned, to have been made near the south side of the entrance, some distance south 

 of the 1907 station. The observations at Terror Cove and at Station C, Campbell 

 Island, appear to have been made almost, if not quite, upon the spots at which the 

 " Erebus " observers worked. 



In New Zealand at the present time the annual rate of change of declination 

 is -h 3'-l ; of horizontal force - 20y ; and of dip + l'-9. 



At Station C, Campbell Island, the observations show that the average change 

 per annum in the total magnetic force over the sixty-seven years has been — 15y, 

 whereas at Christchurch, New Zealand, the average annual change at present over 

 six years is + 6y. Comparing Station VII with the station at the entrance to 

 Port Ross of the " Erebus " observers gives an average increase of total force per 

 annum of + 13y. 



Accurate determinations of latitude were made at Stations V and I^ — 



Station V, eight circum-meridian altitudes of the sun ; latitude deduced, 



50° 44' 43'' S. 

 Station I, seven circum-meridian altitudes of the sun ; latitude deduced, 

 50° 50' 26" S. 



The longitude determined at the depot, Camp Cove, Carnley Harbour, was 

 166° 0' 42" E. 



