Ixiv CONTENTS. 



Se£h IX. All plants poffefs a power of correcting, 

 in a few hours, foul air, unfit for refpiration, 

 but only in clear day-light, p. g8 



X. All plants yield a more or lefs quantity of de- 

 phlogiflicated air in the day-time, when grow- 

 ing in the open air, and free from dark fhade, 



4 1 

 %h The faculty which plants poffefs of yielding 



depblogijlicated air, of correcting foul air, 



and improving common air, is not owing to the 



aft of vegetation, 44 



XII. Plants evaporate by night bad air, and 

 contaminate the common air, which fur rounds 

 them : yet this is far overbalanced by their 

 falutary operation in the day, 47 



XIII. All roots, few excepted, when left out of 

 the ground, yield by day and by night foul 

 air, and infetl the fur rounding air, 53 



XIV. Flowers ooze out by day and by night ah 

 unwholefome air, andfpoil at any time and in 

 every place a confiderable body of air, in which 

 they are placed, 55 



XV» All fruits in general exhale a deleterious 

 air by day and by night, in the light and in 

 the dark, and poffefs a remarkable power of 

 fpreading a poifonous quality throvgh the fur- 

 rounding air, 58 



XVI. The power of plants in correcting bad air 

 is greater than their faculty of improving good 

 air, 62 



XVII. On the effeft of living plants kept in a 

 room, 67 



XVIII. Leaves 



