356 Zach oti Repeating Circles. 



to astronomers, it is not very satisfactory so far as the interests 

 of the science are concerned. Let us now take into conside- 

 ration the results of all these observations, and let us remark 

 the greatest differences between the zenith distances which 

 have been observed, and we shall have the following table : 

 Observations at Dunkirk by M. Dclambre : 



By the pole-star upper culm. 



lower ditto 



By /3 Ursce iVf/??o?/s upper ditto 



lower ditto 



At the observations of |3 Ursce Minoris, at its upper culmi- 

 nation, in which the enormous difference of 36'' occurs, 

 M. Delambre adds the following remark : 



" I reject four series evidently defective, although I could 

 not discover with incontestable certainty what rendered them 

 so bad." Bad indeed, for on the 4th of March he found by 

 16 observations the latitude = 51° 2' 40", 72, and three days 

 after, on the 7th, he found it, by 14 observations, = 52° 2' 4", 36. 

 The real latitude is 52° 2' 15'"'. 



At Paris, in his observatory in the Rue de Paradis, M. De- 

 lambre found the following differences : 



By the pole-star upper culm. 



lower ditto 



By/3 Ursts 3Iinor is upper ditto 



• lower ditto 



M. Mechain, though more adroit and more experienced 

 than M. Delambre, was not more fortunate in his observations, 

 or in the results he obtained. His observations were made 

 at the Royal Observatory at Paris. He began by suppressing 

 more than 800 observations of the upper culmination of the 

 pole-star, made in the interval between the 9th of December 

 1798 and the 6th of February 1799, and more than 400 of 

 the loxver culmination of j3 Uis^e Minoris, made during the same 

 period. He had also observed the upper culmination of that 

 star, as well as the lower culmination of the pole-star; but these 

 observations could never be found. M. Mechain has therefore 

 rejected more than 2000 observations. We may easily guess 

 what sort of agreement they would have exhibited, since we 

 know the reasons which induced this able, patient and sincere 

 astronomer to reject them. This, however, is the very cause 

 of our regret. 



M. Mechain 



