248 NATURAL APPEARANCES 



they draw from the earth. In order to be convin- 

 ced of this, one need only cover a plant with a glass 

 bell, and it will appear that the leaves collect in the 

 night a greater quantity of dew drops than the leaves 

 of the other plants which are exposed to the air. 

 This certainly would not be the case if the dew fell 

 from above, and if it did not rise from the ground. 

 Nothing is more easy than to comprehend how it is 

 formed ; for nobody is ignorant, that the rays of the 

 sun, and the heat which is cast on the earth, continu- 

 ally loosens a multitude of thin particles from off 

 every thing ; some of which rise into the atmosphere, 

 and the rest collect in the form of drops of water. 

 This account of the dew explains to us, how it hap- 

 pens that it is sometimes hurtful, and sometimes not 

 so. Its nature evidently depends on the quality of 

 the vapours of which it is composed. The wind 

 carries away the light exhalations as soon as they 

 are formed, and prevents them from falling in drops. 

 This is the reason that there is most dew when the 

 air is very calm. By this wise plan of the Creator, 

 the plants can vegetate and grow in countries even 

 where there is no rain ; for the soil of those parts 

 being sandy, porous, and very moist underneath, the 

 heat draws out a great quantity of dew, which sup- 

 plies the place of rain. 



