14 CHANGES OF THE MAGNETIC DECLINATION 



Diurnal Inequality of the Declination. — The following table contains the hourly 

 means of all observations at the Winter quarters, between January 10 and March 

 23, 1854. The remaining observations on term-days at a later season have been 

 excluded on account of their isolation. The above period includes the coldest 

 season of the year, and during more than one-half of the period the sun was below 

 the horizon. 



The hourly means were made out separately for each nloiith, the general mean 

 includes seventeen values for each of the twenty-four hours. In January we have 

 complete observations on six days, in February on seven, and in March on four 

 days. The table also contains the monthly means, and all numbers are expressed 

 in scale divisions (one division = 0'.8()). 



