^ß s. Hirayama. 



The mean value of é, (column G of Table X), as computed from 

 Carrington's, Spörer's, and Maunder' s formulœ, is nearly expressed 

 by the formula, ç = 14°.40-2°.83 sin';, which may also be analysed 

 as follows : 



r\,(c of Drift I) + A(ç of Drift II) 



= ^(14°.37-2°.97 sim;0+TV(14°.69-2°.65 sin^;) 



= 14°.40-2°.94 sin';. 

 11. The present investigation, though cursory, leads meto 

 conclude that there are two apparent drifts in the motions of the 

 sun-spots. The angular velocity of Drift I is represented by 



. ç = 14°-37-2°.97 sin-/ 

 and that of Drift II by 



ç=14°.69- 2°.G5sin';-, 

 showing a mean rate of about (/.35 greater than that indicated 

 by Drift I. The mean ratio of the number of sun-spots in 

 Maximum II to those in Maximum I is 1 : 2. This hypothesis of 

 assuming the existence of a secondary drift may be considered a 

 tentative explanation of the phenomena of the distribution of 

 sun-spots with different rotation periods in any particular zone of 

 latitude, and I do not claim tliat the conclusion I have arrived at 

 do more than approximate to quantitative precision. 



Tokyo : 



1912, January 20. 



Publ. June 7th, 1912. 



