356 Dr. Herschel’s Account of the Changes 
situation x'. The consequence of this will be an increase of the 
angle of position ; but, as we know, from the observations which 
have been given, that this angle has been decreasing, it follows, 
that the small star cannot be admitted to have been at rest, if 
We place it farther from us than u. 
( e ) When the smallest of the two stars of our double star is 
supposed to be much nearer than the largest, the effect of 
parallax will carry it beyond . x'. Let its distance from us to 
that of ot. be, for instance, as 3123 to 6076. In this case, while 
a appears to move as far as a", x will be seen to move to x" ; 
where its angle of position x" u" P', will be just io° 53' north- 
preceding, as by observation it was found to be in the year 
1803. But, according to this hypothesis, the distance ex!' x" of 
the two stars, ought now to be nearly double what it was in 
1779; and, since this is contrary to observation, we must also 
give up this last supposition. 
Double Motions. 
(/) Let us now suppose a and x to be in motion, while the 
solar system remains at rest. Then, since there will be no 
parallax that can affect the appearance of these motions, they 
must be real, and proper to each of the stars. But the circum- 
stances that must take place, in order to produce the phenomena 
which have been observed, are so particular, that we shall soon 
find the great improbability of such an accidental arrangement 
of them as would answer the end. It has already been shown, 
in the paragraph (c) of the former Paper, that we cannot place 
the two stars at an equal distance from us ; and it would be the 
height of improbability to suppose them to move in parallel 
planes. But, whatever may be the directions and velocities of 
