Preceffion of the Equinoxes. 517 
§ io. We might now proceed in a fimilaf way to in- 
veftigate the effects of the Moon’s difturbing force, the 
rotation of the earth’s axis, and the equation of the pre- 
ceffion ; but fince thefe proportions are purely mathe- 
matical, and the computations have already been gone 
through by other authors, it will be needlefs to repeat 
them here. 
§11. newton was the firft who attempted to explain 
the preceffion of the equinoxes from its caufes. Since 
his time various other folutions have been given us by 
the molt celebrated mathematicians ; and it deferves to 
be noticed, that, in a cafe where there can be little doubt 
that he was miftaken, other authors have found it diffi- 
cult to agree among themfelves in differing from him. 
M. d’alembert, in the year 1749, printed a treatife 
exprefsly on the fubjedft, and has fince faid that him- 
felf is acknowledged to be the firft who determined 
rightly the method of folving fuch problems, euler, de 
LA GRANGE,FRISIUS,STLVABELLE,WALMESLEY, SIMPSON, 
Emerson, have each confidered the fubjeeft, and perhaps 
the importance of the enquiry would juftify a minute 
examination into the caufe of the agreement or difagree- 
( a ) D’ailleurs, des geometres, vraiment capables d’apprecier mon travail, 
©nt abondamraent fupplee a tout autre temoignage, en declarant que j’ai ouvert 
le premier la route pour refoudre ce genre de queftions* See Opufc. Math, 
vol. V. fur la Preceffion des Ec^uinoxes. 
Vgl. L XIX, Y y y 
meat 
