Motion of the Sun , and solar System. 239 
rest, must either be intirely parallactic, or at least composed of 
real and parallactic motions; in the latter case they will fall 
under the denomination of one of the three motions we have 
defined, namely sa, the apparent motion of the star. 
In consequence of this principle I have delineated the meeting 
of the arches arising from a calculation of the proper motions 
of the 36 stars in Dr. Maskelyne’s catalogue, on a celestial 
globe ; and, as all great circles of a sphere intersect each other 
in two opposite points, it will be necessary to distinguish them 
both : for, if the sun moves to one of them, it may be called 
the apex of its motion, and as the stars will then have a paral- 
lactic motion to the opposite one, the appellation of a parallactic 
center may very properly be given to it. The latter falling 
into the southern hemisphere, among constellations not visible 
to us, I shall only mention their opposite intersections ; and of 
these I find no less than ten that are made by stars of the first 
magnitude, in a very limited part of the heavens, about the 
constellation of Hercules. Upon all the remaining surface of 
the same globe there is not the least appearance of any other 
than a promiscuous situation of intersections ; and of these 
only a single one is made by arches of principal stars. 
The ten intersecting points made by the brightest stars are 
as follows. The 1st is by Sirius and Arcturus, in the mouth of 
the Dragon. The 2d by Sirius and Capella, near the following 
hand of Hercules. The 3d by Sirius and Lyra, between the 
hand and knee of Hercules. The 4th by Sirius and Aldebaran, 
in the following leg of Hercules. The 5th by Arcturus and 
Capella, north of the preceding wing of the Swan. The 6th 
by Arcturus and Aldebaran, in the neck of the Dragon. The 
7th by Arcturus and Procyon, in the preceding foot of Hercules. 
