216 History of Astronomy for the Year 1603. 



equations of conditions which give the means of verifH'ing 

 all the elements. He has brought them to such perfection 

 that the errors amount only to lO"; but the mass of Saturn, 

 reduced to x5To ? is more exact than that deduced from the 

 satellites. 



The oppositioit of Jupiter gives — 2" in longitude. 

 The opposition of Saturn in the month of March gave 

 for the correction of the tables in longitude — 1 7", and in 

 latitude zero. But M. Bouvard will undertake the same 

 labour in regard to Saturn as that which he has announced 

 on Jupiter. 



The disappearance of Saturn's ring, according to the cal- 

 culations of Dusejour_, will not take place till the end of 

 June. 



For the end of December he found only an almost disap- 

 pearance, or an instantaneous disappearance*; a tendency 

 to disappear t- But the disappearance was complete from 

 the 20th of December to the 10th of January, according to 

 M, Mechain and M. Flauguergues, at Viviers. I have 

 thence deduced the place of the node of Saturn's ring in 

 the ecliptic 5' 17° ll'; the observations of 1774 gave 5^ 17'^ 

 29': the dift'erence is small, and makes only 18' in twenty- 

 nine years for the motion of the node of the ring. I found 

 still less for the anterior disappearances %. 



The reappearance took place on the lith of June, accord- 

 ing to M. Flauguergues. 



On the l6th, according to M. Vidal ; and the result was 

 nearly the same. 



Among the rare observations which M. Vidal has sent 

 us, there is one very extraordinary. On the 11th of Octo- 

 ber he observed Jupiter and Venus at the same time as the 

 limb of the sun: they differed only lO' in declination: he 

 saw them together in the field of the telescope. He ob- 

 served Saturn in the meridian 20' before the sun. 



Olbers's planet, discovered on the 2Sth of March 1802, 

 has this year afforded occupation to all the astronomers. It 

 had been lost since the l6th of October 1802 ; we were all 

 impatient to see it aofain : M. Harding, of Lilienthal, first 

 enjoyed this satisfaction; ori the 19th of February he saw 

 it like a star of the twelfth magnitude. 



M. Messier followed it till the momh of September, not- 

 withstanding the extreme difliculty of tccing it with the best 

 telescopes. 



Messrs. Burckhardt and Lalande my iiephcw observed 



* Vol, ii. i^. 12+. t P.ii^c 155. + Aition. art. 3355. * 



