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LXVII.— 0^ AN ABI^ORMAL SOLAR SPOT. By WENT- 

 WORTH ERCK, LL.D. 



[Read, June 15, 1885.] 



For the last three weeks the disturbance of the photosphere has 

 been confined to the southern hemisphere, chiefly between the 

 parallels of 12° and 15°. It has manifested itself in the production 

 of large, isolated spots, and not, as frequently, in numerous small 

 ones. 



The northern hemisphere has been perfectly free from distur- 

 bance. 



On the 9th June a very great spot was observed in lat. 15° S., 

 and 35° E. of central meridian. The umbra, or nucleus, of this 

 spot was very much elongated in the direction parallel to the 

 solar equator. 



June 10, 675. — The disturbance on this parallel was evidently 

 increasing ; the single elongated umbra had then resolved itself 

 into two, entirely distinct, but both enveloped in a common pe- 

 numbra. 



This is not an unusual occurrence ; but the mode in which it 

 took place was most remarkable. Each of the component umbrse 

 was roughly pear-shaped, the small ends pointing toward each 

 other. The penumbra was continuous round the two umbrae, but 

 much constricted at the place of their separation. 



The general appearance strongly suggested an oblong mass of 

 viscous material, stretched till torn asunder by external forces 

 applied at each end, the penumbra maintaining a constant 

 breadth from the edge of the umbra outwards, and therefore 

 being constricted where the breadth of the umbra vanished. 



The appearance presented was utterly inconsistent with the 

 idea of an internal disruptive or explosive force, and seemed 

 absolutely to require the operation of pulling forces applied at 

 each end; or of two powerful currents converging from the fol- 

 lowing side on the centre of the original spot. Next day the 

 penumbra also had divided itself at the point of constriction, and 

 there appeared two ordinary spots, completely separated from each 

 other by a central interval of seven helio centric degrees, or about 

 85,000 iiiileis. 



