making a minute Survey of the Heavens. 47 



Fraunhofer's telescopes of 4- inches aperture, in an illumi- 

 nated field,) we shall seldom or never find a deficiency in the 

 astronomical application of the charts, and shall obtain a re- 

 sult, the surpassing of which would not only be extremely dif- 

 ficult, but would be prejudicial for obtaining a general view, 

 owing to the excessive number of stars which it would be ne- 

 cessary to introduce. But this detail being once attained, the 

 charts will show us at once any thing new, on comparing any 

 part of them with the heavens, provided the magnitude of the 

 star be not less than the limit assumed. Besides the interest 

 naturally attached to a more correct view of the heavens ge- 

 nerally, and the facility thereby obtained for many astronomi- 

 cal observations, such charts would also offer the surest means 

 of enlarging our knowledge of the solar, system, by the disco- 

 very of new planets. Nay, such a result will be highly pro- 

 bable, whilst without such special celestial charts they can 

 only be found by some lucky chance. 



Indeed, there have been repeated attempts towards con- 

 structing charts of this description : and although they have 

 not been crowned with success, it will be sufficient to enume- 

 rate the causes that have impeded their execution, in order to 

 show that they are not now insuperable. The perfection of 

 the celestial charts to a certain limit can only be attained by 

 first laying down on a net work*, or scale, those stars that have 

 been determined by meridional observations, in order that all 

 the rest, intended to be introduced, may be added from esti- 

 mation by the eye, perhaps assisted too by some instrument. 

 By meridional observations alone, even if repeated more than 

 once, we cannot acquire the certainty of having all the stars 

 within the assumed limit. Even the Histoire Celeste contains 

 much fewer stars than are necessary as a basis for perfect charts; 

 wherefore it was necessary to make de novo, a more numerous 

 series of meridional observations. Such a one has now been 

 made at the observatory of Konigsberg, extending over a cir- 

 cular zone of the heavens from — 15° to +15° declination, and 

 containing about 32,000 stars ; which, according to an expe- 

 riment made in a part of the heavens most filled with stars, 

 are quite sufficient. Besides this difficulty, now removed in a 



* [This net work is delineated on the copper-plate engraving which ac- 

 companied the original communication, and which was sent as a pattern. 

 It consists of 100 small squares, formed of faint lines, half an inch (Eng.) 

 asunder; each square comprehending a degree. It is formed on the plan, and 

 on the same scale, as Harding's Atlas ; and therefore it is unnecessary to 

 give a specimen of it here. The plate itself is given in Schumacher's 

 Astron. Nach. No. 88 ; and it may be seen by application to the Secretary 

 of the Astronomical Society, — Sec] 



zone 



