VOL. LXXVl.] PHILOSOPHICAL TRANSACTIONS. 8/ 



last century, and shall venture to give the following results : 1. Continues at its 

 full brightness for about 5 years. 2. Decreases rapidly during 2 years. 3. In- 

 visible to the naked eye for 4 years. 4. Increases slowly during 7 years. 5. All 

 these changes, or its period, are completed in 18 years. 6. It was at its minimum 

 at the end of the year 1 663. 



It does not always increase to the same degree of brightness, being sometimes 

 of the 3d, and at other times only of the 6th magnitude. 



Its mean right ascension, computed from my observations, and reduced to 

 Sept. ], 1782, is 302° 26' 45'^ 



<r Cephei. — This is the last variable star discovered, and again by Mr. Good- 

 ricke. Its changes are very difficult to be seen, unless examined when at its 

 minimum and full brightness. I have lately made some good observations on it 

 thus. 



It was between its least and greatest brightness August 31, at noon, and Sept. 

 26, at 21^: these being compared to my first observations, when also between 

 its least and greatest brightness on Nov. 20, at 3** and Nov. 30, at 15^, 1784, 

 give the mean result of its period 5^ 8*^ 374-™ ; which corroborates that deduced by 

 Mr. Goodricke of 5^^ 8^ 37^"^. — Those that follow are of the second class. 



Hevelius's 6th Cassiopece. — In 1782 I first perceived that this star was missing; 

 nor could I find it in 1783 and 1784. 



A6lh or ^ AndromediB. — This star is said to have diminished in brightness. In 

 1784 and 1785 I found it, by very exact observations, less than u, equal to w, and 

 brighter than d and ;j^. 



Flamsteed^s 50, 52, t AndromediPf and Hevelius's 4 1 Andromedce. — The posi- 

 tion and characters of these stars differ considerably in diflTerent catalogues, and 

 some of them are mentioned by Cassini as having disappeared and re-appeared, 

 Mr. P. gives their brightness as observed in 1783, 1784, and 1785, thus: — 

 Flamsteed's 50th of the 4 . 5th magnitude, and equal, if not rather less than ^ 

 AndromedaB. t of the 5th magnitude, and equal to 46 and 48 Andromedae. — 

 49, 52, and Hevelius's 41, of the 5 . 6th magnitude, and are of the same bright- 

 ness. A star between Flamsteed's 52 and Hevelius's 41 is of the 6th magnitude, 

 or rather less. 



Tychos 20th Ceti. — This must be the star which Hevelius said had disappeared, 

 being Tycho's 2d in the Whale's belly. There can hardly be any doubt but that 

 it is the ^y misplaced by Tycho. This ^ is of the 4 . 5th magnitude, and of the 

 same brightness as the three ^]^ Aquarii. 



Flamsteed's 55th Andromeda, marked Neb. in his Catalogue. — It is mentioned 

 in the latest catalogues of NebulcC that this nebula could not be found. Flamsteed 

 does not mark it nebulous ; nor does it appear to be such, but as a star of the 6th 

 magnitude. There are a few small stars near it, which to the naked eye, when 



