NO. 7.] 



HORIZONTAL INTENSITY. 



75 



not give sufficiently serviceable material for investigation. For the cases in 

 which magnet VI has been used, therefore, I have simply had to take the 

 value found in Hamburg in 1893 for the temperature-coefficient: 



= 0-000638 . 



THE FINAL VALUES OF THE CONSTANTS /t AND C. 



The assumption that the magnetic moment of magnet V, and thus the 

 factor n also, have remained constant throughout the expedition, is made, as 

 already mentioned, the basis of the final calculation of the temperature- 

 coefficient of the magnet. As a check on the correctness of this assumption, 

 I have again calculated ft with the final value of for each of the 8 certain 

 normal days with the following result: 



The values found agree, as the table shows, very well with one another, 

 and I have therefore assumed the mean of all the determinations as the 

 final value of ft for the respective distances e and E. 



No observations permitting of the determination of ft were made with 

 the small declination-needle as deflected magnet during the expedition. For 

 this mounting of the apparatus, I have therefore kept to the determinations 

 in Hamburg in 1893, and in Wilhelmshaven in 1897. I have recalculated 

 the latter, introducing the improved ultimate value of a and obtained: 



