t^:i and positions 0/36 double and triple stars, &c. 361 



^o..^;x:^lY. R. A. 17^^ 4" ; Decl. 26° 18' S, 



36 0phiucni; H. and.3. 243. 



continued. 



In the case of 61 Cygni, by following a similar mode of 

 observing, (but using six stars of comparison instead of two,) 

 I satisfied myself in a very few monthsy of the enormous 

 proper motion of that extraordinary double star. 



To those who may feel disposed thus to attack proper 

 motion, I would hint, how indispensable it is, that their Equa- 

 torial should be well clamped, and that they should wait 

 during the observations of difference of declination, till the 

 earth's diurnal motion bring each of the following stars, 

 opposite that part of the wire where the bisection of the first 

 star was made ; the results will then be charged with no 

 instrumental error, which it is in their power to avoid : the 

 observations also should be conducted as nearly on the meri- 

 dian as possible. '^'^ ' 



When the above was written, I was not aware that the. 

 star 38 Ophiuchi had been observed since the time of Flam- 

 steed ; on examining however Piazzi's catalogue, I find 

 that it stands there under the name of 3 1 Scarpa, and that its 

 place has been determined by 19 observations of that emi-- 

 nent astronomer ; perhaps therefore some light may at the 

 present time, be thrown upon the subject under consideration ;^ 

 but some corrections will be needed by our observations, to 

 render them comparable with those, to which we are alluding. 



The star 36 Ophiuchi is composed of two stars of nearly 

 equal magnitudes, and distant from each other 5".2oo ; whe^i 

 ther Bradley's instruments showed it double, does not 

 appear; nor from Piazzi's catalogue, does it seem that he 

 saw it otherwise than as a single star ; hence it is fair to 



MDCCCXXVI. 3 a 



