786 



SUBANTARCTIC ISLANDS OF STEW ZEALAND. [Magnetic Observations. 



NOTES. 



At Enderby Island and Mount Faye it was impossible to determine the azimuth, 

 as the sky was obscured. These declinations could, however, be calculated at a 

 future date from the observations of the magnetic axis and reference marks (perma- 

 nent) which were taken. At the stations where only one needle was used to determine 

 the dip a correction has been applied. The horizontal intensity as determined by 

 N.A.B.C. magnetometer requires a correction of —0-00013 C.Gr.S. to be applied to 

 reduce to observatory standard (magnetometer No. 1). Dips observed with " field 

 circle " require a correction of + 0'-8 to bring them to the observatory standard 

 (circle 147 ; three needles). 



New Zealand standard time is 11 hours 30 minutes fast of Greenwich mean 

 time. The times as given are counted continuously from midnight (Oh.) to midnight 

 (24h.). The latitudes at Stations I and V were obtained from circum-meridian 

 observations. At Stations II and IV the latitude is from a meridian altitude. The 

 other latitudes are scaled of! from Admiralty charts, as also are the longitudes, the 

 longitude as determined at Station I being taken as a standard for stations in 

 Carnley Harbour, and that given for the Transit of Venus station in Terror Cove 

 for the stations about Port Ross. 



The dips observed with circle 147 (two needles), as given above, require a correc- 

 tion of — 0'-5 to bring them to the observatory standard (circle 147 ; three needles). 



The results of an accurate comparison of the Christchurch Observatory standards 

 with the adopted international magnetic standards has recently been published by 

 the Department of Terrestrial Magnetism, Carnegie Institute, Washington, 



With regard to the character of the rock in the immediate neighbourhood of the 

 stations, it will be useful to note the following : — ■ 



Station I. — On a sandy beach ; granite rocks in the neighbourhood. 



Station II. — On granite rocks. 



Station III. — On a beach of shelly sand ; basaltic rocks not far distant. 



Station IV. — On a beach of basaltic boulders. 



Stations XI, XII. — The rocks chiefly limestone, with dykes of basalt. 



Station XIII. — Rock lavas of intermediate character. 



The nature of the rocks at other stations may be gathered from the report of 

 the geologists. It is significant that the extremely low value of between 7° and 

 8° E. for the magnetic declination at Station V, Auckland Island, accompanies the 

 peculiar geological nature of the rock as seen in the geological map. 



We are indebted to the kindness of Dr. Chree for bringing to our notice the 

 following magnetic observations made by the " Erebus " observers in 1840-41. 

 They are taken from General Sabine's " Contributions to Terrestrial Magnetism, 

 No. XI " (Phil. Trans, for 1868, pp. 371, 388, 397, 408). 



Between November, 1840 



, and April, 1841. 





On Shore at 



Lat. S. 



Long. E. 



Number of Ob- 

 servations. 



Magnetic Declina- 

 tion E. of N. 



Auckland Island . . 

 Campbell Island 



50 32 

 52 33 



16°6 12 

 169 9 



8 

 2 



17 44 

 17 40 



