SCIENTIFIC NEWS. ^ 



the months of December and January: an oscillation, were 

 it but of 2", 9DuId then scarcely escape observation; as w« 

 are indebted to Mr. P.'s analytical investigation for th« 

 knowledge, that its period rannot be a complete year, so 

 that the latitude must undergo a gradual variation, if ob- 

 served rci^ularly at thesame period, 



Mr. Poisson has also investigated some other formulae, 

 with a view to simplify them, and render them of more 

 easy application. The firstobject, to which he has applied 

 them, is the motion of a point attracted toward a fixed cen- 

 tre, according to any given function of the distance: and 

 the second is the rotary motion of a body subjected to no 

 accelerating force. His paper teriniuates with the follow- 

 ing remarkable conclusion, ** 'lih perturbations of the Perturbations 

 rotary motion of solid bodies of whatever figure, to what- goUds^*'^*'*^ 

 ever attractive forces they are owing, depend on the same 

 equations as the perturbations of the motion of a point at- 

 tracted toward a tixed centre. Thus the precession of the 

 equinoxes, and the nutation of the Earth's axis, will be 

 expressed by the same formulae, as give the variations of » 



the elliptical elements of the planets. 



Mr. Legendre has given us some new theories in fluxions, Theore»sia 

 and approximations of easy application. fluxions. 



Messrs. Laplace and Bouvard have each investigated the Motion of the 

 problem of the motion of the Moon being such as always to "^*^'^* 

 present nearly the same face to the Efirth. Mr. Bouvard 

 shows, that there is no need of recurring to approximations. 

 His method, though different from mine [Delambre's], is 

 equally precise and direct ; and his results agree perfectly 

 with those of Mayer, thus atfording an additional proof of 

 the ability of that great astronomer. 



Mr. Burckhardt has revised and enlarged a paper on the PertmbatioTK 

 perturbations of the planets, which he composed in 1803, ^'^^^^ pkocis. 

 but had mislaid. 



To this is added another paper, which will conclude the Ltinar tabl«$. 

 volume for 1808, now about to be published. Theory has 

 not yet been able, or has not ventured, to undertake the 

 calculations necessary for determining the coefficients of 

 the different^ inequalities of the moon, and they have been 

 taken from observation. The raethgd fpllowe<| io these re- ; 

 , . search e|i 



