Life, Researches, and Discoveries of F. W. Bess el. 311 



replaced by the larger and more accurate meridian circle of Reich- 

 enbach, a wider field of inquiry was opened out, and. a task un- 

 dertaken and completed of which astronomy is only now be- 

 ginning to reap the fruits. This was no less than a determina- 

 tion of the places of all the stars, down to the ninth magnitude, 

 in a zone of the heavens extending from 15° south to 45° north 

 declination. Previous to entering upon this great work, how- 

 ever, the new instrument was subjected to a more severe and 

 rigid scrutiny into the divisions of its circle, and the accurate 

 adaptation of its parts (by the aid of a microscopical apparatus 

 contrived and executed by Pistor), than that which its predeces- 

 sor had undergone. It sustained the ordeal to admiration. 

 The zone observations were commenced on the 19th of August, 

 1821, and completed on the 21st of January, 1833, in 536 zones, 

 comprehending upwards of 75,000 observations. The arrange- 

 ment of the work, as printed in the Konigsberg observations, is in 

 the highest degree convenient for reference. Every zone is ac- 

 companied by a small table, by means of which the reduction of 

 any one of the observed objects to a fixed epoch may be per- 

 formed at once, and in the shortest possible time ; so that the ob- 

 servations themselves, by the aid of an index to the zones, have 

 nearly all the advantage of a catalogue, and that of a very high 

 degree of precision. Their actual reduction and arrangement 

 ^ a catalogue was commenced in 1830 by Professor Weisse ; 

 but the promised work has not, we believe, yet appeared. Bes- 

 sel was assisted in the observation of these zones by M. Arge- 

 lander, who, since his removal to the direction of the observato- 

 r y at Bonn, has continued them from the 45th to the 80th de- 

 gree of north declination, the observations being very recently 

 Published in the first volume of the transactions of the Bonn 

 Observatory, in 204 zones. It will be a matter of no small in- 

 vest, when the elements of the new planets which have so re- 

 cently been added to our list shall have become sufficiently 

 k »own to admit of a retrospective ephemeris being calculated, to 

 8ej ttch the Konigsberg zones for missing stars lying in their 

 1*, and corresponding to former places of them. The detec- 

 tion of such will be of inestimable value in the correction of 

 their elements and the theory of their perturbations. 



Future astronomers will reap the rewards of this laborious 

 Wof k ; but there was one subject of astronomical research, of a 

 Poetical nature, which Bessel was destined to commence and 

 cai *y out to its completion, terminating in a discovery of first- 

 rat e importance, in the determination, beyond the reach oi rea- 

 dable doubt or cavil, of the parallax of a fixed star. The 

 to, 61 Cygni, pitched upon for his attack upon this dilhcult 

 question, which had so long bid defiance to the attemps of as- 

 tronomers, and which seemed destined constantly to afford fresh 





