410 THE CHEMISTRY OF THE SUN. [CHAP. 



limit to the enormous energies indicated, and the areas over 

 which these energies hold their sway. One spot, or at least a 

 spot system, was observed in 1858, of 140,000 miles or eighteen 

 earth-diameters in length. Telescopic examination of each 

 minute part of these enormous disturbances indicates that the 

 most violent changes are going on changes which the eye 

 can detect, after a few minutes' interval, in different parts of 

 the spot. 



These changes present us with phenomena of reaction, as if 

 the material carried in the first instance below the upper level 

 of the photosphere had produced a disturbance in the lower 

 regions, followed by the increase in the quantity and brilliancy 

 of the faculous matter and its separation into small masses, 

 while at times the umbra of the spot becomes distinctly 

 coloured. 



I again quote Dr. Peters : 



" The notches in the margin, which, with a high magnifying 

 power, always appear somewhat serrate, grow deeper, to such a 

 degree that the penumbra in some parts becomes interrupted by 

 straight and narrow luminous tracts already the period of de- 

 cadence is approaching. This begins with the following highly 

 interesting phenomenon. Two of the notches from opposite 

 sides step forward into the area, over-roofing even a part of the 

 nucleus ; and suddenly from their prominent points flashes go out, 

 meeting each other on their way, hanging together for a moment, 

 then breaking off and receding to their points of starting. Soon 

 this electric play begins anew and continues for a few minutes, 

 ending finally with the connection of the two notches, thus establish- 

 ing a bridge and dividing the spot into two parts. Only once I had 

 the fortune to witness the occurrence between three advanced points. 

 Here from the point A a flash proceeded towards B, which sent forth 

 a ray to meet the former when this had arrived very near. Soon 

 this seemed saturated, and was suddenly repelled ; however, it did 

 not retire, but bent with a sudden swing toward c ; then again, in 

 the same manner, as by repulsion and attraction, it returned to B ; 



