90 



O. A. Åkesson 



rate in the averages of each particular zone. This appears still more obvious if 

 we compute the means of all the zones. From these means we may infer that the 

 angular velocity determined from the motions of the spots is dependent on the 

 distance from tlie centre of the sun. Moreover, we see that there exists a distinct 

 difference between the two halves. Using the motion in longitude as ordinate and 

 the distance from the central meridian as abscissa, the curve obtained will not be 

 symmetrical about the central meridian, its maximum being situated on the western 

 side of this meridian. 



TABLE XXXIX. 



Mean Values of the Motions in Longitude at different Distances from the Central 

 Meridian 1886-1909. 



L. 





-CO%</<-,50« 1 



-50".o</<-40°.i 



-40''.o<:/<-30".i 



-3J°.o</<-20''.i 



-20'',o<?<:-10".i 



-io''.o<^<:-o°.i 

































nn<l S, 



121 



+ 0,880 



105 



+ 1 .031 



110 



+ 0'.973 



120 



+ l!c25 



132 



+ 0!955 



116 



+ L319 



N, 



" s. 



;m9 



+ 0.769 



385 



+ 0.8C1 



391 



+ 0.917 



370 



+ 0.806 



388 



+ 1,023 



382 



+ 1.327 





' 



478 



+ 0.410 



511 



+ 0.608 



502 



+ 0.709 



509 



+ 0.787 



487 



+ 0.531 



504 



+ 0.803 





.. S, 



335 



+ 0.022 



871 



+ 0.255 



399 



+ 0.510 



375 



+ 0.455 



399 



+ 0.605 



393 



+ 0.605 





» s. 



187 



+ 0.131 



191 



+ 0.149 



202 



— 0.064 



175 



— 0.049 



218 



+ 0.294 



213 



+ 0.486 



Means 



1470 



f 0.410 



1563 



+ 0.562 



1604 



+ 0.631 



1549 



+ 0.635 



1624 



+ 0.669 



1608 



+ 0.874 



Latiti 



de- 



0''.o</<+9°.9 



+10'',o<?<:+19% 



+20''.o<:?<;+28'',9 



+30°.o<:/<+39°.9 



+40''.o</<+49''.9 















n 1 x„ 





Xg 





Xg 



N, an 



1 S, 



130 



+ 1.377 



112 



+ 1,3G0 



106 



+ L113 



116 



+ 1.190 



66 



+ 0'.773 



N., » 



Si 



372 



+ 0.943 



355 



+ 1,035 



335 



+ 1.145 



329 



+ 1129 



178 



+ 0,626 







508 



+ 1.006 



451 



+ 0.730 



465 



+ 0.943 



432 



+ 0.931 



224 



+ 0 228 



■» 





893 



+ 0.795 



352 



+ 0.457 



342 



+ 0.801 



855 



+ 0.711 



192 



+ 0.104 



A', « 



S, 



194 



+ 0.428 



185 



+ 0.797 



170 



+ 0-406 



162 



+ 0.586 



102 



— 0,245 



Means 



1597 



+ 0.899 



1455 



+ 0.796 



1418 



+ 0,905 



1391 



+ 0.903 





+ 0.320 



This strange fact might possibly be explained in the following way, without 

 supposing a different refraction. As we have previously seen, the small spots are 

 more difficult to observe on the western half of the sun than on the eastern. 

 These small spots, part of which are excluded in determining the motions in 

 longitude on the western half, give, however, a smaller angular velocity than the 

 large ones. From this it follows that we ought to have a greater angular velocity 

 from observations on the western half of the sun than from those on the eastern, 

 a fact in close agreement with the results obtained. 



