[ 67 3 



when they remain undifturbed up- 

 on their place. See alfo experi- 

 ments 51, 56, 57, 58, 59, 60* 



SECTION XVII. 



t)n the efeSi of leaving plants kept 

 in a room. 



THO'I think, that the keeping 

 of a few plants in rooms is very 

 indifferent as to the health of the 

 perfons who live in them ; yet it 

 is not fo indifferent for us to know 

 the effects which plants have in 

 reality on the air of the room, that 

 we may avoid danger from any 

 excefs. 



F ',3 The 



