474 Royal Astronomical Society. 



From the observations of the 19th and 26th of March, and 2nd of 

 April, we have computed the following elements : — 



Perihelion Passage, Feb. 27 d, 436953, Greenwich mean time. 

 Long, of Ascending Node. . . . 1°55' 18"* 6 from mean equinox of 



[March 26. 



Long, of Perihelion 277 43 53*7 



Inclination 35 34 0'8 



Perihelion Distance 0-00701906 log q = 7'8462789 



Motion retrograde. 



The ephemeris computed from these elements, after applying 

 aberration, requires the following corrections in order to agree with 

 our observations : — 



This corresponds well enough with the observations to be used in 

 computing the parallax and aberration, and in reducing to a com- 

 mon date the places observed during the same half hour. These ele- 

 ments have some resemblance to those of the comet of 1 689 as com- 

 puted by Pingre. The inclination, however, of the latter, 69° 17', 

 differs too much to be consistent with their identity. Professor Ben- 

 jamin Pierce, of Harvard University, Cambridge, Mass., has recom- 

 puted the observations used by Pingre, and finds for the elements of 

 the comet of 1689, 



Perihelion Passage 1689, December 2 d, 1403, Greenwich mean time. 



o / 



Longitude of Ascending Node. .. . 344 18 



Longitude of Perihelion 271 16 



Inclination 30 25 



Perihelion Distance 0*0103 



Motion retrograde. 

 The elements of the comet of 1843, with a period from 1689, 

 December 2 d, 14G3, to 1843, February 27 dl 4370, represent the places 

 given by Pingre within 5°. Whether the errors of Pingre's places 

 of the comet of 1689, together with the effect of perturbations, 

 amount to 5°, is a subject worthy of investigation. It has never 

 happened, I believe, that two comets have appeared with elements 

 agreeing so well, without being found in the end to be the same. 



Respectfully, 

 Lieut. -Colonel Sabine, R.A., Woolwich. E. O. Kendall. 



