Hi Astronomical Socieij/. 



which is the same with that used in all its former measurements, 

 and of which the cause has been detected too late to remedy the 

 evil. 



After noticing some peculiarities in his mode of observation, 

 and in particular its use of a red illumination of the wires, which 

 he regards as a great improvement, he enters into a more particular 

 examination of the bearing of his present results on the theory and 

 history of the following stars, whose motions he considers as fully 

 demonstrated by them, although some of them had previously been 

 brought into question. 



1] Cassiopese. y Virginis. 39 Draconis, 



7) Persei. rj Coronae. g' Lyrae. 



Castor. n^- Bootis, s" Lyrae. 



!; Cancri. 49 Serpentis. ? Sagittae. 



w Leonis. cr Coronae. 61 Cygni. 



y Leonis. ,a Draconis. S Equulei. 



Ursae. 70 Ophiuchi. ? Aquarii. 



Among these the most remarkable of his conclusions refer to 

 Castor, g" Cancri, ^ Ursae, y Virginis, and tj Coronae. In the cases 

 of Castor and y Virginis, he is enabled, by the kindness of Pro- 

 fessor Rigaud, to produce observations of their positions by Bradley 

 and Pound, which are peculiarly valuable, as they carry back the 

 history of these stars upwards of a century, and enable us to form a 

 much better judgement than heretofore of their orbits, both which 

 appear to be ellipses of considerable elongation. He describes a 

 very ready and easy graphical process by which these orbits may 

 be approximately laid down, and exemplifies it on y Virginis, re- 

 specting which he concludes that the present approach of the stars, 

 and increase of their angular velocity, will still go on for several 

 years, until their distance is reduced to less than a single second, 

 which, considering the brightness of both individuals, will render 

 this a single star to all but the very finest telescopes. Castor he also 

 considers likely, ere very many years have elapsed, to become a 

 close double star, and again to open to a much more considerable 

 distance than at present. 



In the case of ^ Cancri, he is led by his observations to conclude 

 that the motion is retrograde instead of direct, and much more 

 rapid, so that this star has nearly completed a whole revolution. 

 This conclusion is fully confirmed by his observations of the present 

 spring (IS,"]!), and also by the observations of Mr. Dawes, which 

 have been communicated to him very recently, and which agree in 

 a very remarkable manner with his own, and actually suffice to 

 trace the bimestral motion of the star, as had been previously done 

 in the case of ^ Ursas. ij Corona, too, offers, if all the observations 

 can be trusted, a still more remarkable instance of quick rotation, 

 being already considerably advanced in its second revolution since 

 Sir Wm. Herschel's first discovery of it ; but this will require further 

 confirmation, owing to the extreme difficulty of the measures. 



The 



