On the Precession of the Equinoxes. 323 



will ever deserve the patronag;e and encouragement of the 

 poblic, and the auxiliary efforts of the Engineer and the 

 Philosopher. A. B. QUINBY. 



PHYSICS AND CHEMISTRY. 



Art.XIII. — On the Precession of the Equinoxes. 



To the Editor of the American Journal of Science. 

 Sir, 



In examining the Theory, which has long been received, 

 relative to the Precession of the Equinoxes, 1 have recently 

 been induced to consider it questionable, and to account 

 for this interesting phenomenon in a manner entirely new. 

 Not being in a situation, however, to make accurate Astro- 

 nomical observations, or to pursue the subject so far, as to 

 form conclusions perfectly satisfactory, I transmit to you 

 some of the objections, which I have to the prevailing the- 

 ory, together with the method of accounting for this phe- 

 nomenon, recently discovered ; hoping, that the attention 

 of Astronomers will be directed more minutely to this sub- 

 ject, and, that they will remove some of the obscurity from 

 the old theor>, if it is still considered supportable. 



It is unnecessary here to give the old theory at length ; 

 as reference may easily be had to those authors by whom it 

 is described ; and 1 shall notice only such things as are ne- 

 cessary to make known my objections. 



The precession of the Equinoxes has been attributed to 

 the effect of the Sun and Moon on the superior portion 

 of matter about the Earth's Equator, which converts it 

 from a sphere to an oblate spheroid ; and the case has 

 been represented as nearly parallel with that of the revo- 

 lution of the Lunar nodes. 



The objections to this theory, are First, the precise di- 

 mensions of this ring of matter have not yet been ascer- 

 tained ; and different astronomers, with equal confidence 

 form different conclusions relative to its size and shape, and 

 until these are positively known, no rational or conclusive 

 demonstration can be made of the nature and power of its 

 attraction. 



Again, this cannot consistently be considered as a case 

 parallel with that of the Lunar motions. In fig. 1, pi. 3, let S 

 be the Sun, E the Earth, S E the plane of the Ecliptick,A 

 O the ring of matter about the Equator. Now, it is evi- 



