in the Axis and Poles of the Earth. 313 



ecliptic, o'' T and =5^, would be transferred to s and yj', and 

 north and fouth to eaft and weft. 



A queftion now arifes, whether anv traces- exift on the 

 furface ot" our globe which I'oem to (how that the inclination 

 of the earth's axis has ever changed either fuddenly or pro- 

 grelTively, or whetlier the pole has altered its place? On the 

 lirft view, it would appear that this qiieltion ought to be an- 

 fwered in the affirmative. 



Many naturalifts and geologifts, in order that they might 

 more eafily explain the general deluge, and why marine pro- 

 duftions are often found at a contiderable depth under the 

 earth's furfJace, or on the lops of hioh mountains; how the 

 remains of aiiftral plants, and of tericiirial and aqu.itic ani- 

 mals, could have been conveved to the northern regions, and 

 buried there in the bofom of the earth; liow the difierent 

 flrata of mountains have been formed, and other phseno- 

 mena of the like kind, have been able, as is well known, to 

 contrive no better hvpolhefis than to fuppofe that iome de- 

 rangement of the poles of the earth, or changes in the in- 

 clination of its a.xis, mufl. have taken place in frnicr times. 



But, in my opinion, the determination of this queftioij 

 belongs rather to aflronomers than to geologifts, becaufe by 

 the former it may be confidered under a more general point 

 of view, viz. what connexion exifts between the pofition of 

 the earth's axis and the fun, and- the attraftive power in the 

 folar fyftem ; and what obfervations have been made in re- 

 gard to the pofition and direction of their axes, from which, 

 by analogical realoniui.', we mav explain the relation between 

 caufes and eft'cfts when fuch changes take place. 



The ableft altronomers and geometricians have fliown that 

 the fmall annual reccllion of the e(juino<il;ial points to the 

 weft, of about 51 ieconds, and the revolution of the earth's 

 axis around the poles of the ecliptic, which thence follows in 

 the courfe of 25,700 years, arife from the united aAion of 

 the attractive power of the fun and moon on the fpheroidal 

 form of the earth. As long, therefore, as this attraction of 

 the fun and moon arts in an uuitorm manner, it feems to be 

 impoUihlc that anv continued or very perceptible changes in 

 regard to the earth's axis can take place. 



It is, however, found by olifervations, that in the conrfe of 

 many centuries an alteration, though very fmall, has taken 

 place in the inclination of the earth's axis. At prelent it is 

 23 minutes greater than it was in the time of Hipparchus, 

 that is, al)ove 2000 years ago. 



In confcnucnce of this obfervation it has been apprehended 

 that the echptic may, at feme future period, coincide with 



tlie 



