132 Mr. Pigott's Investigation of the Changes 
Its rotation on its axis was, in 17 96, estimated at 62 \ days, 
from a mean of six observations of its greatest and least 
brightness. Here follow about 2 6 similar determinations, most 
of them the results of very accurate observations ; and as they 
probably will in future be compared with others, I have exa- 
mined them repeatedly with the utmost care, attending parti- 
cularly to the progression of their changes. 
Table I. 
Dates when at its greatest 
Brightness. 
Magni- 
tudes. 
Dates, when at its least 
Brightness. 
Magni- 
tudes. 
1796. September 17 
5 
1796. September 3 
6 
November 13 
5 — 
October 22 - 
6 
1797. May 14: 
5 + 
1797. July 10 - - 
5-6 
August 7 
5 
September 15 
6 
October 15 - 
6-5 
November 6 
6 
1798. July 29 - 
5 + 
1798. July 10 - 
6 
October 25 - 
5-6 
September 15 
9.0 
December 5 : : 
5 6 
November 10 
6 
17 99- J une 1 :: 
6.5 
17 99- J ul y 4 
7 
August 7 
5 
September 16 
6 
October 11 - 
5 + 
November 5 : 
6.7 
1801. July 14 : 
5 
1801. June (middle): 
6 
September 24 
5 
August 21 
6.7 
October 16 - 
6-5 
The -}- and — > annexed to the magnitudes denote them to 
be more or less bright ; the doubtful results are marked 
with dots ; all the others are esteemed exact, except those of 
August 7, 1797, an d August 21, 1801, which are in a small 
degree less so. From these determinations the rotation on its 
axis may be computed as follows. 
