DETERMINATION OF THE ELEMENTS OF THE SEX'S SPIN. 



285 



Also 



/ :r+F=6°.968+0\038=6°.996= 7°.006) 



for 1861 

 N = N'+X cösec I = 74".523 + I e . 480 = : 76°.003 ) 



Here we sec that the value of the node is larger than any of the values 

 given at the beginning of the paper. The value of the inclination is 

 nearly the same as thai given by Sporer. 



As a check on this result, I calculated the variations of latitudes 

 at equal intervals of 30° degrees of longitude, by summing the three 

 successive columns of the Table III. and dividing the results by the 

 average number of spot occurrences. Also to see if there is a notice- 

 able secular change in both node and inclination, I divided the interval 

 of 24 years into three separate periods : first, from 1861 to 18G8 ; 

 second, from INCH to 187!» : third, from 1880 to 1884. Separate 

 reductions were made for these three distinct periods. The resulting- 

 differences of latitude and the number of spots are shown in Table 

 IV. 



Table IV. 



