[ =>S ] 



of deviation DAC, as determined by the diagonal of the pa- 

 rallelogram. 



In this folution Mr. Emcrfon fays, " the earth being an oblate 

 " fpheroid, the fphcre is encompaffed with a folid cruft going 

 " round the equator in the manner of a ring ; now the efFed of 

 •' the forces of the fun and moon upon this cruft, and the motion 

 " communicated thereby to the whole body of the earth, is what 

 " we are to enquire after." He then calculates the force of the 

 fun upon the annulus, and fuppofes this whole force efficient; 

 he next fuppofes this whole motive force to a£l at the diftance 

 of the centre of gyration from the centre of the earth, and thence 

 deduces the motion generated in the plane of the equator about 

 one of its diameters. It appears therefore, that he fuppofes the 

 whole motive force of the fun to be efficient on the annulus, fe- 

 parately confidered : and 2dly, that this efficient force is equal 

 to the efficient force on the fame annulus, when connected with 

 the earth; which, cxclufivc of the error detcdted by Mr. Milner, 

 arc the very fame falfe hypothefes with thofe adopted by 

 Simpfbn. 



Bdt here a queftion naturally arifes, if the error of Newton's 

 calculation be as great as is pretended, whence comes it to pafs 

 that the refult of his calculation agrees fo exadly with phas- 

 nomena; for on fuppofition, that the preceffion arifing from the 

 force of the fun alone is but 9* 7", the preceffion caufed by 



Vol. VII. D the 



