C. Wille. Magnetiske Observationer. 



C. Wille. Masiietical Observations. 



Efter den for Nordhavs-Expeditionen lagte Plan skulde 

 der søges udfort Observationer til Bestemmelse af Jord- 

 magnetismens Elementer saavel i Land som i Søen. Til 

 dette Øjemed anskaffedes og medbragtes følgende Instru- 

 menter : 



Et Uuitilar-Magnetometer. No. 38. af Elliott Brothers 

 i London. Instrumentet blev veriticeret og dets Konstanter 

 bestemte ved Observatoriet i Kew. 



Eu liden Theodolit af Olsen i Kristiania, laant af 

 den geografiske Opmaaling. 



Et Inklinatorium af John Dover, Charlton. Kent. 

 undersogt i Kew. 



Et Admiralitets-Standard-Kompas. veriticeret ved Kom- 

 pas-Observatoriet . i Deptford. 



Flere Azimuth-Kompasser. 

 ' En Fox-Cirkel No. 30 af John Dover, med Hjælpe- 

 apparater og Slingrebord. 



Flere Kronometre og Sextanter. 



Et Observationstelt fra Berglens Arsenal, velvillig ud- 

 laant af Armé-Iutendanten. 



Jeg skal nu særskilt behandle Observationerne . paa 

 Landstationer og Observationerne i Soen. 



A. Observationer paa Land-Stationer 

 og deres Resultater. 



a. Deklination. 



Begge til Magnetometret horende Magneter var Kolli- 

 mations-Magneter, med Skalaer i Objectivglassets Brændplan. 

 Da Instrumentet ikke var forsynet med Plan-Spejl til De- 

 klinationsbestemmelse. men kun havde et Hulspejl til at 



The Scheme of Work approved for the Norwegian North- 

 Atlantic Expedition. was, if possible. to comprise obser- 

 vations for determining the elements of terrestrial magnetism, 

 alike on shore and at sea. With this objeet in view, the 

 following instruments were provided. 



A Unifilar Magnetometer. No. 38. made by Elliott 

 Brothers, of London. This instrument was verified, and 

 had its constants determined, at the Kew Observatory. 



A small Tbeodolite. by Olsen of Christiania, obtained 

 on loan from the Geographical Survey. 



A Dip-Circle. hy John Dover, of Charlton. Kent, 

 examined at Kew. 



An Admiralty Standard-Compass. verified at the Com- 

 pass Observatory, Deptford. 



Several Azimuth-( 'ompasses. 



A Fox-Circle. No. 30. by John Dover, with auxiliary 

 apparatus and gimbal-table. 



Several Cbronometers and Sextants. 



A Tent. kindlv lent Ironi the Bergen Arsenal. 



I will now pass on to the observations. describing 

 separately those tåken at the land-stations and those made 

 at sea. 



Observations at Land-Stations, 

 and tbeir Results. 



Declination. 



Both of the magnets belonging to the magnetometer 

 were collimator-magriets. with the scale in the focal jilane 

 of the object-glass. The instrument not being provided 

 with a plane mirror for observing the declination. but 



