194 - 
Mr. Pigott’s Obfervafions on 
Algol. 
The period of Algol, difcovered by Mr. Gogdricke, gave- 
us forae new light into the nature of the fixed ftars. Though 
the phaenomena feem to attrjd the attention of moft aftrono- 
mers, {fill there are fome points which require further invefti* 
gation. Its degree of brightnefs, when at its minimum , is 
different in different periods ; and alfo, I think, when at its 
full, It is fometiraes brighter than a. Perfei, and at other times 
lefs. Whether thefe differences return regularly after a certain 
number of periods remains yet to be examined. My laft obfer- 
vations, when it was at the middle of its minimum , are, 
h. 
1.785, July 8, at 11 50 undoubtedly lefs than § Perfei* 
July 3.1 r at 9 50 equal to ? Perfei. 
J a remarkable obfervation ; rather lefs than ^ Perfei | 
Sept. 12, at 10 45 
f evidently brighter than £ ; nearly of the 3d mag e 
Mayer’s N° 420, lately difcovered to be variable by M. Koch a 
A few years before 1782, M. Koch faw the N° 420 un- 
doubtedly lefs than the N° 419 of Mayer’s Catalogue. 
I ft February 1782^ he found them both exactly of the fame 
brightnefs, therefore of the 7th magnitude. 
From an extra£l of a letter I have lately feen, the variable 
was of the 9th magnitude in April, 1783, and of the 10th in 
Aprils 1784. 
1 have often feen the N° 419* but never the variable, though^ 
I have frequently looked for it with a night-glafs, and on the 
4th of April, 1785, in a 3*feet achromatic tranfit inftrument. 
Variable 
