Mifiellanea Curioja. 377 



Now we know that the more eafily the Was 

 ters can obey the Attraction, with the more Force 

 are the Tides moved ; but fince, as Mr. Halley 

 has determin'd St, (*) our Atmofphere is extend- 

 ed to 4.5* Miles, whereas the middle depth of 

 the Ocean is but about half a Mile ; it is plain, 

 that the Air revolving in a Sphere about 10O 

 times larger than that of the Ocean, will have a 

 proportion ably greater Agitation. 



Befides, Rocks, Shelves, and the inequality 

 of Shoars are a great flop to the Accefs and Re- 

 cefs of the Sea : But nothing repels the rifing 

 Air, which is alfo of fuch tbinnefs and fluidity, 

 that it is eafily driven, and runs every way. 



Nor ought we to omit, that it is the univer- 

 fal Law o? Bodies Attracted, that the Force 

 of Attraction is reciprocally as the Squares of 

 their Diftances fo that the Action of the Sun 

 and Moon will be greater upon the Air than 

 upon the Water, upon the Account of its Near- 

 nefi. 



But the Confideration of the Elafticiry is (till 

 of greater Moment here, of which this is the 

 nature, that it is reciprocally as the PrelTure, fo 

 that the incumbent Weight being diminimed by 

 the Attraction, the Air underneath will upon 

 this fcore be mightily expanded. 



Thefe and fuch like Caufes will make the Tides 

 in the Air to be much greater that thofe of the 

 Ocean j nor is it neceffary to our purpofe to de- 

 termine, by nice Calculations, their particular 

 Forces ; it is fufficient to have proved that thefe 

 Motions muft both be Univerfal, and alfo return 

 at certain Intervals. 



B b 4 Now 



(a) Pbilof.Tranf. Nf°i8i. 



