150 Mr. Herschel's and Mr. South’s observations of the apparent 
16.93 years, i77°-75 were described, being at the mean rate 
of io°.4 99 per annum. In the next period, of 1.74 years, 
the angle described was 12°.03, or 6°.9i4 per annum ; while 
in the succeeding short period of 1.54 years, the motion 
amounted only to 6°. 84 or 4^442 per annum. It is therefore 
at present rapidly decreasing, and the maximum annual mo- 
tion must, at some period between 1803 and 1820, have 
greatly exceeded io°.499, and perhaps may have amounted 
to 20 or 30°. This consideration would lead us to place the 
perihelion of the orbit in the north-preceding quadrant, be- 
tween the 30th and 60th degree from the parallel, and to 
suppose its plane greatly inclined to the visual line, in a plane 
not far from that passing through the eye and the major axis 
of the orbit ; and this agrees well with the change of dis- 
tance, which is certainly less at present than in 1782, though 
the estimation by diameters is necessarily very uncertain. 
In the present imperfect state of the data, it would be use- 
less to enter into any minute investigations respecting the 
elements of the orbit ; but when twenty or thirty years ob- 
servations shall have enabled us to trace precisely the varia- 
tion of the angular motion up to the aphelion, and to as- 
certain, by direct observation, the periodic time and mean 
motion, the principles of physical astronomy may be applied, 
and the case is one particularly favourable to their application, 
so that we may hope one day to obtain a precise knowledge 
of all the most important points respecting this interesting 
system. 
It is to be regretted that owing to an error in the place of 
this star in Bode’s Catalogue, it was not observed by us at 
an earlier date ; the comparison of our observations with 
those of M. Struve being very desirable. 
