Hiftory of AJlronomji for the Year 1801. 119 



appeared in the Connnffance des Temps for the year 12. 

 have feen, with pleal'ure, my immediate hiccelFor and deareft 

 pupil purl'ue the lal)uur which my mafter Lemonnier made 

 me undertake, fiFiv vears ago, in imitation of Tycho Brahe, 

 who began his refearclies on the planet Mars, and who put 

 Kepler in the wav of making his difcoveries by means of the 

 fame planet. lie will foon employ himfelf on tables of 

 Venus, taking into account her perturbations. 



For Saturn, the error has been found + i" in longitude 

 and — 9" in latitude. Delambre has made new refearches 

 to correit the error of 30" in the tables of Jupiter, but it has 

 been found in the obfervations made for 60 years: we 

 muit therefore fearch for the caufe of it in the theory, and 

 in fonie new irregularities. 



Bouvard has terminated his calculations of all the per- 

 turbations of the planets, each by the action of all the reft, 

 according to the theory of Laplace. The refult will be new 

 tables, which will be ftill more correft. 

 ' C. Burckhardt has made an analytical and numerical cal- 

 culation of the terms of the fifth order, which were not be- 

 fore taken into account in confequence of the length of the 

 calculations. He has found that thcfe terms incrcafe the 

 great irregularity of Saturn by one minute. 



C. Chabrol has calculated obfervations of the fun, and 

 has found that 7" mull be dedu(iled from the longitudes 

 given by our tables. But Delambre has undertaken to cal- 

 culate 7 or 800 obfervations of Bradley, applying 8 or 10 

 new equations furniftied bv calculations of the attra6lion. 

 The eccentricity of Jupiter and the earth give equations for 

 the fun which amount to from 8 to (.)'\ We fliall therefore 

 foon have new tables of the fun ftill more correct than thofe 

 publiilieJ by Delambre ten years ago, and to which it ap- 

 peared that nothing could be added. 



For mercury, the error in my tables did not exceed 10'^. 

 An oblervation of \'cnus on the •24th of May gave me an 

 error in the tables of -1- 30". This feeins to indicate that 

 we ought to deduct 13'^ from the cjioch, but that the equa- 

 tion of the orbit is good. 



The OjHimJJ'ancc dcs Temps for the year 12 (1804), which 

 has juft appi-ared, contains every thing moft interefting that 

 has occurred in regard to aftrononjy during the laft year. 

 Curious refearches relpeo.ting the theory of the moon, by 

 Laplace; new tables of Mars, by Lefran^ois-Lalande ; a 

 new catalogue of (hirs reduced, making the number 1 1,300, 

 ^cing a continuation of thofe in the preceding vijlumes; 

 iwiporlant u^i/rvalious^ tables, and calculations, by Me- 

 II 4 chaiuj 



