TERRESTRIAL MAGNETISM. 703 



netically at 8 a.m., and a maximum westerly deflection at 2 p.m., 

 at Port Kennedy as at other places of observation. 



Before elimination these effects are marked by the greater 

 disturbance deflections at these times in the opposite directions. 



At Port Kennedy what is magnetically north is geographically 

 S.W., and at Point Barrow magnetic north is about N.E. 



U. Magnetic Observations made in the Second German Ex- 

 pedition on the East Coast of Greenland, in 1869-70, 

 by Captain KoLDE>>rEY, 1874. 



The instruments used by this expedition were — 



(1.) A portable magnetometer. 



(2.) An inclination-needle. 



(3.) An induction magnetometer by Weber, consisting of a coil 

 which could be rotated through 180° about an axis 

 which could be placed either vertical or horizontal. The 

 galvanometer to be used with this coil was an astatic 

 needle, but this was found to be too delicate, and one 

 of the needles was taken off, and only one needle 

 employed. 



(4.) A small needle was employed for observations of horizontal 

 intensity. 



By means of the theodolite of the magnetometer the bearing of 

 a small cairn on the highest point of Walross Island was deter- 

 mined, and the azimuth was found to be N. 123° 11' 10''. 



The Declination. 



Observations for determining the absolute declination were 

 made generally on two consecutive days about twice a month, 

 during December 1869, January, February, March, and June 

 1870. In all these observations the declination was nearly 45° W., 

 and the mean value is 45° 6' 7" W. Generally it was found on 

 trial that there was no correction required in the declination for 

 the torsion of the thread. 



Observations on Changes of Declination on Term Days. 



It had been previously arranged with Professors Klinkerfus 

 and Kohlrausch at Gottingen, that on the 21st of the month, for 

 24 hours, terminal observations of changes of declination should 

 be made. 



For the first 10 minutes of every half-hour (Copenhagen time) 

 observations were to be made every 2 minutes, and during the 

 remainder of each hour at every 5 minutes. 



From these observations the hourly and daily means are deduced 

 and recorded in the tables. 



The observations were made on the term days in December, 

 January, February, and March ; also on January 5, February 11, 

 and March 4. 



On January 5, at 9 o'clock (Copenhagen time), the aurora was 

 seen, and there was, about 9.30 p.m., very great disturbance of 

 the magnetometer. 



