20 



O. A. Åkesson 



da^'s. During eight days the spot is within 60" from the central meridian. The 

 co-ordinates etc. during these eiglit days, we write on seven cards only, as we 

 also need for each card the difference hetween the longitudes and latitudes on 

 two consecutive days. 



The quantities written on the cards I designate as follows : 

 X = the longitude of the spot, 

 ß = » latitude » » 

 = AX cos ß = the motion in longitude of the spot multiplied hy cos ß, 

 y = Aß = » » » latitude » » » 



/ = the distance from the central meridian, 



A = the area of the whole spot expressed in millionths of the sun's 



visible hemisphere, 

 (o = logA. 



When the observations have been transferred into a catalogue of this kind, 

 it is possible to classify tlie material from different points of view without too 

 much work. 



