PiftlV. of the Earth 



within the Surface of the Earth is not 

 liable to lb fudden VicilStudes, or fo 

 quickly fpent and difperfed, as is that 

 which is upon it, and in the Air. This 

 therefore, the Pores of the Earth re^ 

 maining ftill as free, and open, as ever, 

 continues to fend out the mineral 

 Steams as before, but in lefler and lef- 

 fer quantity, anfwerably to the gra- 

 dual Diminution of this Heat. Which 

 Steams, though now fent up to the 

 Surface of the Earth only in leffer plen- 

 ty, may be much more offenfive and 

 tnifchievous than in the hotter Months 

 when it came forth in far greater. For 

 the Sun s power being in thofe Months 

 alfo greater, it then ftraitways hurries 

 thefe Steams up into the Atmofphere : 

 whereas in the colder, its power being 

 lefTened, it cannot bear it up fo faft; 

 fb that it ftays and ftagnates near the 

 Surface of the Earth, fvvimming and 

 floating about in that Region of the 

 Air wherein we breath ; where it muft 

 needs be much more pernicious than 

 when born up to a greater height, and 

 lb farther out of the v»^ay. And this is 

 indeed much the Cafe of Foggs : parti- 

 cularly of thofe which we frequently 

 cfcferve after Sun-fetting, even in our 



P 2 hot* 



