NATURE-STUDY LESSONS. 177 



LII.-FOG, MIST AND CLOUDS. 



1. (a) What becomes of all the vapor constantly form- 



ing on the earth ? 

 (dj. Does it all remain invisible ? 



2. Make observatioiis in the morning and evening 

 along a river bank, in a marshy place, in a low valley, 

 and state the results of your observations. 



3. Why was the vapor seen in the places you were 

 directed to observe rather than at other places? 



4. {a) Why was it seen at those particular times of 



the day? 

 (d) What was the condition of the atmosphere ? 



5. When and why did it disappear ? 



When vapor is condensed and floats very close to the surface of the 

 earth it is called Jb^ or misi. 



6. When or where else have you seen such fleecy 



forms of vapor? 



When the condensed vapor is visible in great masses high up in the 

 atmosphere such masses are called clouds. 



7. {a) Under what conditions is the invisible vapor of 



the air condensed ? 

 (Jj) Infer the origin of clouds in the upper air. 



8. (a) Observe the quietness, rapidity, grace and direc- 



tion in which clouds move. 



{V) What is the cause of their movement ? 



{c) How can clouds be moving in different direc- 

 tions at the same time? 



9. {a) Observe the different kinds of clouds. 



ip) The following are the most common forms : — 

 (i) Feather-cXowAs (cirrus). When clouds are 

 high above us and are very light and 

 feathery. They may be white or bluish. 



