104 The Natural Uiflwy Part IV", 



places where their Dung lyes heap'd 

 up. That 'twas this which occafioned, 

 in fome, an Opinion that Nitre pro- 

 ceeds forth of thofe Aninaals, and their 

 ExcremeBts; whereas it is found rai- 

 led up, and convened or colIe8:ed in- 

 differently and as well in Buildings 

 where Animals rarely or never come, 

 as in thofe they ordinarily frequent ; 

 not to mention phat which is found 

 fometimes in confiderable plenty at 

 great depths in the Earth : in the Wa-? 

 ter of Springs, of Rivers, of Lakes, 

 and, in fbme Farts, even of the Sea it 

 felf; whereof more largely hereafter. 

 That, in fuch places where the Earth 

 contains Nitre within it, though there 

 be no fuch adventitious Heat, if that 

 Heat which is almoft continually 

 liearaing out of the Earth be but pre- 

 fferved, its EXifBpation prevented, and 

 the Cold kept olFby fome Building or 

 ether like Coverture, thu alone is or- 

 dinarily fuiicient to raife up tte Nitre, 

 and bear it out at the Stirface of the 

 Earth, (unlefs its Egrefs be impeded 

 by Pavements, or the like Obftruftions) 

 and mount it up into the Air, as far as 

 thofe Buildings wilt permit. For, the 

 Cielings and Walfe ftopping it in its 



Afcent, 



