distances and positions of 380 double and triple stars, &c. 211 
| Bootis continued. 
to attribute to the small star a motion of — o".35 in R.A., and 
— o".o7 in declination, those of the large one being — o".23, 
and — o".i8. This, though very possible, is not very pro- 
bable, unless we admit a connection of some kind between 
the stars, and other circumstances conspire to throw a doubt 
on the validity of the opposite conclusion. The first is, that 
either the position of 1804, or that of 1792, is certainly in- 
correct. The observation of 1791, when taken in combina- 
tion with that of the following year, shows that about that 
time the angle of position must have been exactly a right 
one, the small star then being in the act of changing qua- 
drants. Even with this concession, supposing the position to 
have been exactly north in i79i-2,and assuming this (1791.8) 
as an epoch, the angle described in the 10 preceding years will 
have been 24 0 , while in the 1 1 succeeding ones it amounted to 
no more than 7°i (up to 1803.25, the mean between the ob- 
servations of 1802 and 1804) or o °.68 per annum, Yet this 
rapid diminution of angular velocity has not continued, for in 
the next 20 years, up to 1823, we find an angular motion of 
13 0 , or 0.65 per annum, and taking only the observations of 
the last four years, it exceeds a degree per annum. These 
considerations indicate a considerable error, either in the 
measures of 1802, 1804, which corroborate each other, or in 
that of 1782, which is marked “ very exact.” Here then we 
have a choice of difficulties, but fortunately a few years will 
enable us to decide. If the relative path of the small star 
be really the strait line it appears to be, the angle of position 
will never reach 50° np, and the angular velocity will diminish 
continually from the present moment. On the other hand, 
