246 ESSAY ON DEW, &c. 



a greater quantity of fluid, than a similar plant 

 exposed at the same time to the open air. 

 Again ; the small quantity of air, contained in 

 the case, must soon be replete with moisture, 

 after which, the whole of what is further 

 emitted by the plant will necessarily assume 

 the form of a fluid, whatever may be the con- 

 dition of the external atmosphere ; whereas, 

 during even the clearest night, only a part of 

 the smaller quantity of moisture, emitted by 

 the exposed plant, will be condensed on its 

 surface. In the last place ; notwithstanding 

 the circumstances, which favour the appearance 

 of moisture upon inclosed plants from their own 

 transpiration, still the quantity observed on 

 them is said to be, for I have made no experi- 

 ment myself respecting this matter, much less 

 considerable, than what is seen upon plants of 

 the same kind, exposed to the air for the same 

 time, during a calm and serene night. 



