168 SCIENCE OF COMMON THINGS. 



Dew on rocky and on fertile Boils. Dew most abundant after a hot day. 



it is not so freely condensed as it passes over gravel, 

 because gravel is not so cold as the grass. 



1O8S Why does dew rarely fall upon hard rocks and barren lands ? 



Because rocks and barren lands are so compact and 

 hard, that they can neither absorb, nor radiate much 

 heat / and (as their temperature varies but very -little) 

 very little dew deposits upon them. 



1O83 Why does dew fall more abundantly on cultivated soils than on 

 barren lands f 



Because cultivated soils (being loose and porous) 

 very freely radiate by night the heat which they ab- 

 sorb by day ; in consequence of which they are much 

 cooled down, and plentifully condense the vapor of the 

 passing air into dew. 



1OS4 Show the wisdom of the Creator in this arrangement f 



Every plant and inch of land which needs the moist- 

 ure of dew is adapted to collect it ; but not a single 

 drop is wasted where its refreshing moisture is not 

 required. 



1O85 When is dew most copiously distilled t 



After a hot day in summer or autumn, especially if 

 the wind blows over a body of water. 



1OSG Why is dew distilled most copiously after a hot day ? 



Because the surface of the hot earth radiates heat 

 very freely at sunset, and (being made much colder 

 than the air) chills the passing vapor and condenses it 

 into dew. 



108*7 Why is there less dew when the wind blows across the land, than 

 when it blows over a body of water ? 



Because the winds which blow across the.Zan^ are 

 dry and arid / but those which cross the water are 

 moist and full of vapor. 



1088 How does the dryness of the wind prevent dew-falls? 



As winds (currents of air) which blow over the land 

 are very dry, they imbibe the moisture of the air ; in 

 consequence of which there is very little left to be con- 

 densed into dew. 



1089 Why is meal very subject to faint on a moonlight niyhtt 



