334 Description and Use of the

with him to its heliacal rising, or an archof the fame quantity on the other side ofthe globe, through which the fun must;have passed from the time when the starset heliacally, to its setting with the fun,which, as in the former cafe, added to thepoint of the ecliptic, in which the fun iswhen the star rises with him, gives the pointhe is in at its heliacal rising; and in thelatter cafe subtracted from that point of theecliptic the sun is in when the star sets withhim, leaves the point he is in at the famestar’s heliacal setting.

Thus having found the points of theecliptic in which the fun must be when anystar rises or sets heliacally, against those pointsin the kalendar, on the horizon, you obtainthe month and day.

As the distances of the fixed stars fromone another have been found the fame inall ages, it is probable they have no realmotion of precession, but only an apparentone, caused by the retrocession of the equi-noctial points, which are found to recedefrom their ancient stations at the rate of 50seconds every year; this alters their longi-tude, but their latitude does not vary : hence

their