of Double Stars. j 6 1 
diicover beyond a doubt a motion in two ffars that are very 
dole together, though it fhould amount to no more than a 
tenth part of a fecond of a degree, provided that motion be in 
fuch a direction that the effed of it be thrown upon the 
angle of pofition ; wherein, with fome of the ffars of the 
firff: clafs, it would occalion an alteration of io, 20, 30, or 
more degrees. 
I have marked all thofe ffars in my catalogue which have 
been obferved by Mr. mayer and other affronomers with an 
j 
afferifk (*) affixed to the number that they may be known ; 
thofe with the mark of a dagger (f) have been obferved by dif- 
ferent affronomers before Mr. mayer. Among the ffars which 
are not marked, will be found feveral that have been obferved 
by Mr. mayer ; but, on comparing them together, it will be 
feen, that they are obfervations of different fmall ffars ; for 
inffance, Mr. mayer (Ad.. Acad. vol. IV. p. 296.) obferved a 
fmall ffar near Rigel at the diffance of 1 ' o",$ JR* in time, and 
2 ' 55 // ,2 in difference of declination north preceding Rigel. 
In my fecond clafs (the 34th ffar) we alfo find Rigel ; but the 
fmall ffar I have obferved is one which’ has not been feen by 
Mr. mayer, and is at a diffance of ho more than 6 ' if'. Pofi- 
tion 68° 12' fouth preceding and fo on with other ffars. 
I have ufed the expreffion double-far in a few inftances of the 
fixth clafs in rather an extended fignification : the example of 
flamstead, however, will fufficiently authorize my applica- 
tion of the term. I preferred that expreffion to any other, fuch 
as Comes, Companion, or Satellite ; becaufe, in my opinion, 
it is much too foon to form any theories of fmall ffars revolving 
round large ones, and therefore I thought it advifeable carefully 
to avoid any expreffion that might convey that idea. I am 
Vol. LXXII. Y very 
