172 STUDIES OF NATURE. 



that country, not only becaufe they are a great de^ 

 licacy for the table, but becaufe the white, when 

 dried, becomes hard as a flint, and fufceptible of 

 a polifli fo beautiful, that they are cut and fet as 

 rings and other trinkets. 



I could eafily fwell this article, by demonflrat- 

 ing the geometrical impoffibility that our Globe 

 fliould have been detached from that of the Sun, 

 by the tranfit of a Comet, becaufe it muft have, 

 on the very hypothefis of this impulfion, been hur- 

 ried along in the Sphere of the Comet's attradion, 

 or carried back into that of the Sun. It has, in 

 truth, remained in the fphere of the Sun's attrac- 

 tion ; but it is not eafy to conceive how it never 

 came to approach nearer, and how it comes to 

 maintain the diftance of nearly thirty-two millions 

 of leagues, while no Comet prevents it's returning 

 to the place from which it fet out. The Sun, it is 

 faid, has a centrifugal force. The Globe of the 

 Earth, therefore, muft be retiring from it. No, it 

 is alleged, becaufe the Earth has a conftant ten- 

 dency toward that Luminary. It muft, accordingly 

 have loft the centrifugal force, which fliould adhere 

 to it's very nature, as being a portion of the Sun. 



1 could go on to fwell the article, by farther de- 

 monftrating the phylical impoffibility, that the 

 Earth fliould contain in it's bowels fo many hete- 

 rogeneous 



