132 EFFECTS OF HEAT. 



Q. How can WINDS CHANGE the SHAPE of 

 CLOUDS by altering the position of their parts ? 



A. Because clouds are so voluble and 

 light, that every breath of wind changes 

 the position of those ves'cicles or bubbles. 



Q. What are Hie general COLOURS of the 

 CLOUDS ? 



A. White and grey, when the sun is 

 above the horizon : but red, orange, and 

 yellow, at sun-rise and sun-set. 



The blue sky canuot be considered as clouds at all. 



Q. Why are the LAST CLOUDS of EVENING 

 generally of a KED tinge ? 



A. Because red rays are the least 

 refrangible of all; and, therefore, are 

 the last to disappear. 



Q. What is meant by being "LESS EEFRAN- 

 GIBLE ? 



A. Being less able to be bent. Blue 

 and green rays being very easily bent 

 (by the resistance of the air) are thrown 

 off from the horizon ; but red rays not 

 being bent back in the same way, give a 

 tinge to the evening clouds. 



Q. Why are MORNING CLOUDS generally of 

 a RED tinge? 



