of a Variable Star . 61 
I have reafon to alter, in fome meaiure, my opinion on this 
head. Even Algol does not feem to be always oblcured in 
the fame degree, being perceived to be lometimes a little 
brighter than % Perfei, and fometimes lefs than it *. Thefe 
feeming irregularities, however, do not appear to affeft the 
period ; for if we compare the fame precife phafes together, it 
will be found {till regular. This may, 1 fuppofe, be accounted 
for, by a rotation of the ftar on its axis, having fixed fpots that 
vary only in their fize. 
I need not fay, that the fituation of $ Cephei, on account of 
its great northern declination is fuch, that its changes may be 
obferved with great advantage in thefe latitudes, it being always 
fufficiently elevated above the horizon. To this circumftance are 
alfo owing its various changes of pofition, which, I find, 
affeft the comparative brightnefs of the ftars a little ; but, as 
thefe differences are very trifling, I fhall take no further notice 
of them. 
If you think this account worthy of notice, I beg you will 
be fo kind as to communicate it to the Royal Society. 
I remain, with great regard, &c. 
JOHN GOODRICKE. 
* This will appear from an attentive examination of the obfervations of that 
liar’s diminution in my two late Papers, which U'ere printed in the LXXIIId and 
LXXIVth volumes of the Philofophical Tranfadlions, I did not take much notice 
of it then, becaufe I thought the difference was too fmall to be relied on ; but the 
obfervations I have made fince feem to confirm that it does really diminifh a 
little unequally. M. Mechaim, in a letter to Mr. E. Pigott, mentions the 
£a& c 
