OF ARTS AND SCIENCES. 321 



eijuatorial belt varied so much that on some days it appeared fully 

 three times as broad as it did on others, extending to unusually high 

 latitudes north and soutli, which at times reached 40° and 45° on either 

 side of the equator. On several occasions, this broad, rosy equatorial 

 belt did not appear symmetrically distributed on the sides of the 

 equator, but was more or less one-sided, the southern being usu- 

 ally the side where it was most extended. In 1877, the disturbances 

 on Jupiter were few and on a small scale, and after the middle of June 

 the surface was remarkably quiet, the few changes noticed occurring 

 principally within the equatorial belt. This state of quietness has con- 

 tinued till now, with the exceptions of the appearance of the red spot 

 in 1878, which occurred without any great commotion or changes of 

 the surface, and the bursting out of the row of round black spots in 

 October, 1880, which subsequently developed into the broad rosy belt 

 now seen in the northern hemisphere of tlie planet. 



In regard to the question put forward by Mr. Marth, in the 

 " English Mechanic," whether anything is known of the red spot in 

 1876-77, and whether it was then seen and observed, I can only 

 give the following answer. In the year 1876 I began observing 

 Jupiter on May 16, and observed it on every clear night as late 

 as Oct. 19, and made during that interval 125 drawings of the planet. 

 Nothing resembling the red spot in the slightest degree was seea 

 during these observations. In 1877 the observations were begun on 

 April 11, and continued on every clear night as late as Dec. 9, 142 

 drawings beinff made of its configuration, and no traces of the red 

 spot were seen. In 1878, only a few observations were made before 

 September ; two drawings were made in February, two in March, one 

 in May, one in June, and fifteen in September, previously to my seeing 

 the red spot on the 25th of that month. My observations, therefore, 

 do not give any information about this interesting object before Sept. 

 25, 1878. The negative evidence given by my observations amounts 

 almost to certainty that the red spot did not exist before the year 

 1878. 



Cambridge, March 5, 1881. 



VOL. XVI. (n. s. viii.) 



