178 NATURE-STUDY LESSONS. 



(2) Rain-clouds (nimbus). When low and 



heavy, sometimes covering the whole 

 sky like a grey veil. 



(3) Wool-pack clouds (cumulus). Resembling 



great packs of wool, or the appearance 

 of hills piled the one upon the other. 



(4) Layer-cXowAs (stratus). Seen most fre- 



quently in the morning, in layers one 

 above the other, or in layers side by 

 side. 



10. Observe the beauty of the different kinds of clouds. 



1 1. What are the uses of clouds to the earth ? 



12. {a) Hang a triangular glass prism up in the win- 



dow when the sun is shining to observe the 



colors of the rainbow. 

 {U) At what times of the day have you observed 



rainbows ? 

 {c) Describe the relative position of the sun, the 



bow and yourself. 



Rainbows are formed only amidst water particles and during sunshine. 

 The drops of water act as so many prisms, separating the sunlight into its 

 constituent colors. 



id) What is the shape of rainbows ? 



LIII.-EAIN. 



1. From the drying of clothes on the line, the drying 

 of the roofs of houses and side-walks, the wasting of the 

 snow while the ground is frozen, and the drying up of 

 ponds, infer what must be the relation of the air to water 

 vapor. 



2. Reviewing your experience with condensation, tell 

 which kind of air, warm or cold, retains the more 

 moisture. 



