344 Mr. herschel’s Agronomical Ohfervations , &c. 
remain of a circular form : for, adding the aberration 
5 9 W to the length i w , the whole becomes i"; and adding 
59 v/ to fcarce any breadth at all, the whole breadth will 
alfo become nearly 1". 
keill fays, “ It is probable, that the greateft part of 
“ this ftar is covered with fpots and dark bodies, fome 
“ part thereof remaining lucid; and while it turns about 
“ its axis, does fometimes lhew its bright part, fome- 
“ times it turns its dark fide to us; but the very fpots 
“ themfelves of this ftar are liable to changes, for it does 
“ not every year appear with the fame luftre. Some- 
“ times it refembles a ftar of the fecond magnitude ; in 
“ other years in can fcarcely be reckoned among ftars of 
“ the third order; nor are the times of its vifiting us 
“ always of the fame duration.” 
