[ H ] 
fun? I may here take notice of a curious in ft a nee 
of a nucleus being divided into two parts, which 
fell under my own obfervation. On October 8th, 
1770, the fpot s, Tab. IV. haft a fmall jutting 
in of the luminous matter, upon the oppofite tides 
of the nucleus, which, by the 10th day, had ad- 
vanced contrary ways, fo as to meet, by which 
means the nucleus was now divided into two parts, 
as reprefented by fig. t. It was here very re- 
markable, that the parts of the umbra oppofite to 
this cut in the nucleus, were dilated as in fig. /. 
May not this dilatation have been occafioned by 
the rapid flowing in of the luminous matter into 
the deep channel below? 
Is not the property mentioned in the 8th article, 
•namely, that the nucleus of a fpot vanifhes fooner 
than the umbra, alfo agreeable to the prefent 
views? from this ftate oft the phenomenon, we 
fuppofe that that part of the fun’s dark body, 
which had been uncovered and expofed to our 
view, when the fpot firft broke out, is now again 
juft overflowed by the gradual inundation of the 
luminous matter. But, after the nucleus thus dis- 
appears, may there not however, in many cafes, 
be ftill left a cavity in the luminous matter, large 
•enough to be perceived? and will not this. cavity, 
fo long as it continues, give the appearance of a 
fmall undivided umbra? and will not this umbra 
ftill be perceivable, till the luminous matter, by 
continuing to flow in, has filled up the cavity? 
.after which, will not the place of the umbra ac- 
quire the lame luftre with the reft of the fun’s 
iurface, .and thus will not all traces of the fpot 
vanilh 
