f 7 3 
when I firft got fight of it,- 1 had not an opportu- 
nity of obferving it long that day. Next day be- 
ing the 23d, I. had a curiofity to fee ifc again, and 
fo repaired to my telefcope, in order to examine, if 
any alterations, in the fize and figure, had taken 
place fince laft obfervation. The air was ft ill fa- 
vourable, and I again faw the fpot, it having its 
nucleus and umbra very fharply defined. I now 
found however a remarkable change for the 
umbra, which before was equally broad all round; 
the nucleus, appeared much contracted on that • 
fart which lay towards the center of the difc ,, 
whilft the other parts of it remained nearly off 
their former dimenfions. 
This change of the umbra feemed fomewliati 
extraordinary,- as it was the very reyerfe of what 
I expeCted from the motion of the fpot towards the 
limb. But next day, at 10 o’clock, I had another 
obfervation, and difcovered changes, which were 
ftill more unexpected. The diftance of the fpot 
from the limb was now about 24". By this time,, 
the contracted fide of the umbra above mentioned- 
had. entirely vanifhed ; and the figure of the nu- 
cleus was now remarkably changed, from whatdt 
had been the preceding day. This alteration of the 
figure appeared evidently to have taken place upon 
that fide which had now loft the umbra, the 
breadth of the nucleus being thereby, more fud- 
denly impaired than it ought to have been,, by the. 
motion of the fpot acrofs the difc. Fig. 1,2, [Tab. I.] 
reprefent the appearance which the fpot had on 
the 23d and 24th days. 
Regarding 
