358 Zach on Repeating Circles. 



see why you will not make observations at Evaux conjointly 

 with Delambre" (p. 624). We know perfectly well the 

 reason of this repugnance. 



In the beginnuig of the year 1797, M. Mechain went to 

 make observations at Carcassonne. He made but few. M. De- 

 lambre thinks that, in fact, he suppressed them. He says, 

 (p. 479, ) "It is very improbable that M. Mechain passed all 

 the time from the 1 7th of January to the 20th of March in 

 idleness; we can only sujipose that he communicated to us 

 only those observations with which he was fully satisfied, and 

 unmercifully proscribed all the others for some irregularities 

 which would, perhaps, have rendered them precious for the 

 theory of refi-actions. It is particularly extraordmary that he 

 should not once have attempted to observe /3 UrscB Minoris." 

 He did, no doubt, attempt it ; but he probably destroyed those 

 observations which never satisfied him. He was always per- 

 suaded that those which he made with those cursed repeating 

 circles (for so he called them in the society of his friends), were 

 good for very little ; but this duty was forced upon him. At 

 Carcassonne, then, he made onlyobservations of the pole-star, 

 which gave 



Base du 

 Greatest Number Syst. Met. 

 Differ. of Obs. Vol. II. 



At its upper culmination 1,''93 200 p. 488 



At its lower culmination 1, 93 234 p. 488 



In the month of July, 1796, M. Mechain went to Perpignan, 

 and observed there only the zenith distances of one star, /3 Ursa: 

 Minoris, and that only at its upper culmination. M, Delambre 

 says (p. 493), that he has never been able to find the originals 

 of these observations, and that he has been obliged to take 

 them entirely from copies of the calculations of the latitude. 

 The result is, that in 152 observations of that star, the greatest 

 difference was 6",81.— (P. 502.) 



In 1793 and 1794, M. Mechain was in Spain. He made 

 observations in the city of Barcelona, and in the citadel of 

 Montjouy. He took with him two repeating circles ; one of 

 which he gave up to the Milanese astronomers (p. 504). — 

 This is the same instrument of which we spoke in vol. iv. p. 95 

 of this Correspondance, where we related the singular accident 

 which happened to us with relation to it. 



M. Mechain did not content himself with observing only the 

 two circumpolar stars in Ursa Minor; he added two others, 

 ^ UrscB Majoris and « Draconis, and two zodiacal stars. The 

 gi'eatest differences are given in the following table : 



By 



