CHAPTER III. 



The Latitude Motions of the Sun-spots. 



A. Characteristics of the Motions in Latitude. 



In treating the latitude motions of the spots exactby the same method has been 

 employed as in treating the motions in longitude. However, in dividing the material 

 of observation a class-interval of 0'.5 instead of I'.o lias been adopted. In table 

 XX I have given the distribution of these motions in latitude and in table XXI 

 the computed values of the characteristics. 



Mean and Dispersion. The problem of the latitude motions of the sun-spots 

 has been tlie subject of several investigations. Whether an actual latitude drift 

 does exist seems, however, from these investigations to be undecided. Carrington, 

 from the material embraced in his investigation (Nov. 9, 1853 — Mars 24, 1861), has 

 thought himself able to draw the conclusion that for spots north and south of 

 -f 20° and — 20° respectively the motions towards the Poles are predominant, while, 

 on the contrary, the motions towards the equator predominate between 10° and 20°. 

 The motions towards the Poles, according to Carrington amount on an average 

 to 2' a day and are about double the size of the opposite motions. From what I 

 have been able to find in literature this assumption of Carrington has not sub- 

 sequently been confirmed. From the vast material of observation which is the basis 

 of this investigation, nothing can be inferred that can support this assumption. 

 Looking at table XXI where is the mean of the motions in latitude (-|- for the 

 northern and — for the southern motions) no similar connection between the lati- 

 tude motions and the latitudes of the spots appears. On the contrary, northern 

 motions of the spots seem to be predominant in the northern as well as in the 

 southern hemisphere. 



Since this latitude drift assumed by Carrington is also stated in text-books ^ 

 as a fact which may be considered settled, I must once more emphasize that in 

 tlie material embraced in this investigation, there is nothing whatever to support such 



See for example Peingsheim: Physik der Sonne, page 59. 



