Advertifement. 

 fuch Precipitations, as I JpeaJ^of. And 

 the Phenomena and Confequi. vts of fuch 

 operations may in divers cafes prove 

 conducive both to the Difcovery of Phy- 

 sical Caufes , and the Produ&hn of 

 nfeful ejfeSfs\ though the particulari- 

 zing of fuch Phenomena do rather 

 belong to a Hiftory of Precipitations, 

 than to fuch a Difcourfe as that which 

 follows, wherein I propofed not fo much 

 to deliver the latent Myjieries as to 

 inveftigate the Mechanical Gaufes of 

 Precipitation. 



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