of a Variable Stan $$ 
May 22, at 12 } h. equal to, if not brighter than, 7 Lacerte ; 
think it brighter than t Cephei. 
May 23, at n| h. feemed fometimes equal to, though gene- 
rally lefs than, 1 Cephei and 7 Lacertae. 
Having now delivered the obfervations, from whence I 
have deduced the preceding conclufions, nothing more relative 
to this fubje£t remains to be mentioned, except the determina- 
tion of the period ; in the doing of which I muft follow nearly 
the fame methods as have been ufed in fome preceding papers* 
It is very evident, from a rough calculation, where only fmgle 
periods or very ihort intervals are ufed, that it is about five 
days and eight hours. In order to determine this period with 
greater exa&nefs, I have, in the following table, collated fome 
of the moft precife phafes. The firft five are times when $ Ce- 
phei was obferved to be equal to 7 Lacertae during the courfe of 
its increafe of brightnefs, which proceeds rapidly. The five 
next are fimilar times, with this only difference, that as it was 
not then a&ually obferved to be equal to 7 Lacertae, a proper 
allowance from the neareft obfervations was made on fuppofi- 
don that the changes are fimilar in every period. The ten laft 
are affumed times between its leaft and greateft brightnefs, 
which determinations can hardly err more than a few hours, as 
the whole increafe is completed in thirteen hours ; but even 
were it fo, the periods deduced from them would ftill be exaft, 
'becaufe the intervals are very long. 
