810 PROCEEDINGS OP THE AMERICAN ACADEMY 



About the begiruiing of January, 1880, the red spot began to assume 

 the regrilar oval shape which it has, with but very slight modifications, 

 since retained. These modifications of form consisted principally 

 in that one of its ends appeared narrower, giving it therefore an 

 egg-shape, as that observed on the 1st of November. Its northern 

 margin has also frequently been observed to be deformed, appear- 

 ing jagged and indented, principally on Aug. 26, Sept. 29, and 

 Dec. 10 of last year. The serrations, projecting on the red spot, 

 sometimes appeared as bright nodules, as if the narrow band sepa- 

 rating the red spot from the equatorial belt had been composed at 

 these times of brilliant cumulus-like forms having a higher level than 

 the spot itself. 



Although comparatively steady now, the red spot varies almost from 

 day to day in length, as well as in breadth ; but most of the time the 

 variations are so slight that the greatest attention is required to notice 

 them, and for most observers it is only once in a while that they 

 become apparent. 



The color of the red spot is also subject to some variations, but 

 usually they are slight; and, as these phenomena are more delicate 

 than mere changes of form, it usually requires an expert and trained 

 eye to see them. Apart from the changes in the intensity of its 

 color, which are quite frequent, the variations of color which came 

 under my notice are few, the greatest being, as stated above, when the 

 clear red color of the spot lost its purity, and became muddy and 

 lie-de-vin color. Most of the time, the variations in the intensity of 

 the red spot could be attributed to the state of our atmosphere, but 

 sometimes, as in the above case, they seemed to be real, as the 

 pink color of the equatorial belt was not affected, as it would 

 have been if the cause were atmospherical. It will be shown 

 below that sometimes, also, the piuk color of the equatorial belt 

 increases considerably in some parts, while it remains unchanged in 

 others. 



Throughout the whole month of November, 1880, 1 had the per- 

 sistent impression that there were two small, round, black spots, or 

 specks, on the red spot ; one being not far from its preceding end, 

 while the other, behind, was a little to the west of its middle, both 

 appearing to be a little nearer the southern than the northern border. 

 On Nov. 30, 1 had the satisfaction of finding that my impressions were 

 correct, as I plainly and distinctly saw two small, round spots at the 

 place wliere I had perceived them so many times before. One of these 

 black specks was observed independently by Mr. Alvan Clark, Jr., on 



