Sun Viewing and Drawing. 443 



the edge of the penumbra. He watched it for another hour, 

 when his impressions were put beyond a doubt, and he called 

 in a friend, a good observer, to corroborate the observation. 

 Both himself and companion saw that the patch was distinctly 

 drawing rapidly in towards the central umbra, and by three 

 o'clock in the afternoon it had advanced two-thirds of the 

 distance (= 12") between the margin of the penumbra and the 

 umbra, at the same time becoming more condensed and 

 elongated in the direction of the usual striations on the 

 penumbra.* 



Fig. 3 shows the spot as it appeared about noon on 

 January 28th. It was now beginning to diminish in area from 

 what it was on the 26th, and the subordinate spots of the 

 group were also beginning to break up ; the photosphere, in 

 other words, was beginning to re-assume its ascendancy; a 

 sort of cicatrizing process, if we may so say, was setting in. 



The spot was now, however, and had for three days pre- 

 viously been interesting, from the presence of a well-defined 

 but ragged promontory or bridge, which floated over the 

 umbra and divided it into different portions, as may so often 

 be observed in the solar spots, At this time the promontory 

 was not more luminous than the general penumbra to which it 

 was attached, and it was consequently, in all probability 

 floating at about the same level with it, and of the same tem- 

 perature. 



Bat on January 29th (see Fig. 4), not only had the pro- 

 montory greatly altered in shape, but it was now as bright as 

 the photosphere itself, with which indeed it seemed now in 

 direct communication, by means of luminous streaks of con- 

 siderable width, with which the penumbra had been invaded, 

 showing either that the promontory of the previous day had 

 risen up to the level of the photosphere and become equally 

 luminous with it, or that it had sunk down altogether and 

 melted away (as the writer and others have observed them to 

 do), and that its position had been occupied in part by an 

 indraught apparently of luminous matter from the vast circum- 

 ambient ocean of photosphere. However this may have been, 

 on January 30th the penumbra had again in turn inclosed and 

 isolated the luminous matter in question ; though it did not 

 permanently hold it a prisoner; for by January 31st the photo- 

 sphere had so energetically invaded the principal spot from 

 both sides, as to completely divide it into two spots. 



In short, the battle of the solar elements was decided ; and 



on February 1st (the last time the writer was enabled to see the 



group), the spots were still further dispersing and diminishing; 



and had utterly disbanded themselves, and disappeared, ere 



* In the Plate these atrial ions are rendered somewhat too distinct!/. 



