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SECTION XXII. 



Some remarks on the green matter 

 which fettles at the bottom and 

 fides of the jars in which water is 

 left flanding* 



THIS green matter, which feems 

 to be of the vegetable kind, was 

 firft found by the Rev. Dr. Prieftley 

 to yield very pure dephlogifticated air: 

 but it ceafes at laft to yield more air 

 if the water of the jar is not re- 

 newed 7 which ought therefore to 

 be done now and then. 



It is wonderful that this matter 

 feems to be never exhaufted of 

 yielding dephlogifticated air, though 

 it has no free communication with 

 the common atmofphere, frcjm which 



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