120 
the eastern limb of the sun, and was then a fine spot of not 
less than the 3rd magnitude, and, after undergoing many 
considerable changes of form and structure, was finally 
observed very near the western limb, on the 21st of June, as 
a spot of only the 9th or 9^ magnitude, and from its previous 
rate of decrease it is probable that it would become entirely 
extinct in four or five days afterwards. Its duration, there- 
fore, would not be less than 70 days, and it thus affords a 
striking instance of the fact that frequent and extensive 
changes of form and structure do not necessarily tend to 
produce an early extinction of a spot. Between the 20th of 
April, at 5h. 13m. G. M. T., and the 15th of June, at 
5h. 30m., it moved through 783’3 degrees of longitude, or at 
the rate of one sideral revolution in 25'74 days. On April 
20th its heliographical latitude was 14° 11' N., and on June 
15th 14° 2' N. These results indicate a direction and rate 
of drift which agree very nearly with the results which Mr. 
Carrington has obtained for other spots in and near the same 
parallel of latitude. 
