The Systematic Motions of Sim-Spots. 



15 



fact lias led me to assume that the sun-spots belonging to Drift II 

 are about ^ of the whole. 



9. If we adopt Faye's empirical formula fur solar motion, 

 then our results may be expressed as follows: 

 ? = 14°.37-2°.97 sin;., for Drift I. 

 ç = 14°.69-2°.65 sin;, for Drift II. 

 In order to exhibit how these formulœ satisfy the obser- 

 vations, I give the following table. 



Table XII. 

 Comparison of Computed with Observed Angular velocities. 



It will be noticed that the above formula for Drift I nearly coin- 

 cides with the expression, ^=14°.37-3°.10 sin'; deduced by Faye. 



10. By examining all the spots which lasted for more than 

 six consecutive days, Mr. and Mrs. Maunder (loc. cit. p. 818) have 

 deduced another formula, ç=875'. 7=^164' sin';, which nearly 

 corresponds to the mean values in the last line of Table I. This 

 formula may be analysed as follows: 

 i(ç of Drift I)-l-|(,- of Drift II) 



=Kl4°.37-2°.97 sin';0+l(l-i°ö9-2°.65 sin';) 

 = 14°.61-2°.73 sin';=876'.6-163'.8 sin'A 



That the last expression practically coincides with their 

 formula shows that the latter is greatly influenced by Drift II. 



