242 Royal Astronomical Society. 



him in either of the stars. On turning upon it Mr. Bishop's equa- 

 torially-mounted achromatic telescope, having an aperture of seven 

 inches, and focus of nearly eleven feet, armed with a power of 320, 

 though' the character of the night (October 27) was very indifferent, 

 I was immediately struck with the elongated appearance of the 

 smaller of the two stars ; and having applied higher powers, I pro- 

 cured measures of the direction of the elongation. I have since 

 obtained two other sets with power 420, with which, in best mo- 

 ments, the elongated disc was slightly notched. The results of the 

 three nights' observations are : — 



October 27, Position = 208° 40' Weight = 12 



— 31, ... = 208 25 . . . = 11 



November 4, ... =208 44 ... = 18 



Mean = 208 38 



The estimated central distance = 0''G or 0"*7. 



" It is extremely improbable that so acute an observer as Struve 

 should have failed to recognise an appearance which is now so ob- 

 vious and measurable with a much smaller instrument, if the star 

 had then presented the same aspect as at present — the Dorpat re- 

 fractor being capable of distinctly separating stars of the 8th or 9th 

 magnitude whose central distance does not exceed 0"*4. Most likely, 

 therefore, this star constitutes a new binary system ; and it is highly 

 desirable that, during the remainder of its present apparition, ob- 

 servations should be obtained by different individuals possessing 

 instruments of sufficient optical power. To the notice of such, I 

 beg earnestly to commend it. 



" I may embrace this opportunity of announcing that the obser- 

 vations made during the last sixteen months at Mr. Bishop's Ob- 

 servatory afford satisfactory proof of binary character in several in- 

 stances where it had been only suspected to exist, and of a very 

 large amount of orbital motion in some binary systems previously 

 known as such. The close pair of e Equulei are decidedly more 

 distant than when observed by Struve in 1835 and 1836. Within 

 the last four years, 4 Aquarii has advanced 20° in its orbit ; in which 

 interval the star H i. 39 (2 3062) has changed its position to the 

 extent of about 40°, and y Corona nearly 50°, with a central di- 

 stance of scarcely 0"'5. The alteration is also striking in £ Herculis 

 (now measurable with a five-foot achromatic) and in 2 2107 ; while 

 r Ophiuchi, which for years defied the power of the Dorpat telescope 

 even to elongate it, has now opened out to the extent of nearly a 

 second between the centres of its component stars. Supposing Sir 

 W. Herschel's measure of the close pair of £ Cancri, taken in 1781, 

 to be exact, that remarkable binary system will now have completed 

 a whole revolution since that date, that is, in 59 years. 



" W. R. Dawks." 

 " Mr. Bishop's Observatory, Regent's Park, 

 Nov. 12, 1840." 



A Supplemental Catalogue of the Right Ascensions of Fifty-five 



