in the relative Situation of double Stars , See. 371 
y leading to O, not expressed in the figure. By an observation 
of Feb. if), 1782, we have the angle F y x — 7 0 37' north fol- 
lowing ; and the proportion of the apparent diameter of y to that 
of x has been given as 5 to 4. It has also been ascertained, that 
the vacancy between the apparent diameters, when the first 
angle of position was taken, was ^ diameter of the small star ; 
and the last angle of position being 6 ° 21' south following, with 
a distance between the stars of f diameter of the small star, we 
obtain the two points or centres of the small stars xx', through 
which an ellipsis abxx'cd may be drawn about y. This will be 
the apparent orbit in which the small star will be seen to move 
about y, by an eye placed at O. And the inclination of the 
orbit to the line in which we see the double star, will be had 
sufficiently accurate to enable us to give a calculation of the 
several angles of position that have been taken. The ellipsis we 
have delineated shows that the small star, in its first situation x, 
could not be much past its conjunction at b, and that, conse- 
quently, in passing from x to x', the parts of the apparent 
elliptical arch, which are projections of the real circular arch 
hh'y would be described in times nearly proportional to the 
time in which the whole arch has been described. Upon these 
principles, the 3d column of the following Table has been cal- 
culated. 
