[ xxxix ] 



a great deal of its own air, and will 

 therefore be apt to abforb the air 

 from the leaves. It may alio hap- 

 pen, that every pump-water may 

 not be found equally as good as 

 that which I met with in my coun- 

 try dwelling, though as yet I have 

 no pofitive reafon to think fo ; 

 but I have fome grounds to believe, 

 that water drawn from an open well 

 is far inferior in goodnefs to that 

 which is forced up by a pump, as 

 the former is too much expofed to 

 the open air. 



By calling an eye upon the ex- 

 periments related in this work, it 

 will be eaiily underfTood, why, in 

 every experiment of this kind, 

 fome difference in the refult will 

 commonly be obferved ; for the 

 peculiar degree of goodnefs of the 

 dephlogifticated air obtained from 

 c 4. the 



