Tar all ax of the Fixed Stars . 103 
giius, 1 Caftiopeae, ^ Cygni. And if he can fee all theie, he 
may pafs over into the fecond clafs, and direct his inftrument 
to fome of thofe that were pointed out as objects for the very 
beft telefcopes, where, I fuppofe, he will loon find the want of 
fuperior power. 
The fourth, fifth, and fixth claffes contain double ftars that 
are from 15 to 30", from 30" to i\ and from 1' to 2' or more 
afunder. Though thefe will hardly be of any fervice for the 
purpofe of parallax, I thought it not amils to give an account 
of fuch as 1 have obferved ; they may, perhaps, anfwer ano- 
ther very important end, which alfo requires a great deal of 
accuracy, though not quite fo much as the inveftigation of the 
parallax of the fixed ftars. I will juft mention it, though fo- 
reign to my nrefent purpofe. Several ftars of the firft magni- 
tude have already been obferved, and others fufpected, to have 
a proper motion of their own t hence we may fuimife, that 
our fun, with all its planets and comets, may alfo have a 
motion towards fome particular part of the heavens, on account 
of a greater quantity of matter collected in a number of ftars- 
and their furrounding planets there fituated, which may pei- 
haps occafion a gravitation of our whole folar fyftem towai ds 
it. If this furmife fhould have any foundation, it will fhew 
itlelf in a feries of fome years ; as from that motion will ante 
another kind of hitherto unknown parallax *, the inveftigation 
of which may account for fome part of the motions already 
obferved in fome of the principal ftars ; and for the purpofe of 
determining the dire&ion and quantity of luch a motion, accu- 
rate obfervations of the diftance of ftars that are near enough 
to be meafured with a micrometer, and a very high power of 
* See the note in the rev. Mr. mitcheLl’s paper on the Parallax of the Fixed 
Stars, Phil. Tranf. vol. LVII. p* Z S 2, 
telefcopesy 
