NO. 7.] 



HORIZONTAL INTENSITY. 



69 



DETERMINATION OF THE CONSTANTS. 

 DIRECT DETERMINATIONS. 



The constants employed in the calculation of the horizontal intensity, 

 according to the formulae given on page 64, are the temperature coefficient a, 

 and the quantities C and p. 



These constants, as already mentioned, were determined by observations 

 in Hamburg, between the 3rd and the 9th June, 1893, with the following 

 results, given in Dr. NEUMAYER'S manuscript: 



In order in the first place to get an idea as to how the constants C 

 and /it had remained during the expedition, I first deduced their value from 

 the complete series of observations taken after the return in Wilhelmshaven, 

 in April, 1897, employing the value of the temperature coefficient , found 

 in Hamburg in 1893, as no later direct determination of it has been made. 



The calculations gave the following result: 



