Lessons in the School-yard. 139 



south side of the building ? Why ? Where is it warmer 

 near the house or out in the field ? Why ? 



Such facts as these will help us in all our work : Why is 

 Mr. Clark's cow-shed open on the south side and shut on the 

 north ? Why are Mr. Ryan's rose-houses fixed with their 

 roofs sloping toward the south ? Why has Mr. Moore put 

 his garden on the south slope of the hill ? Why does snow 

 remain longer where I live than where Sanford lives ? Why 

 do the cows always get on the south side of the fences in 

 cold weather? When the sun shines on the ground, it 

 warms the air, and if we can have a fence, or shed, or wall 

 to keep the wind from blowing this warm air away, it will 

 be warmer for our plants and animals. 



When I came to school this morning, I saw that Elsie had 

 al Ithe geraniums and heliotropes covered with papers. Why 

 did she do that, Irving ? " To keep the cold out." " To 

 keep them from freezing." Why does such treatment pre- 

 vent plants from freezing, Mattie ? " Because the papers 

 keep the air under them very quiet, and the wind cannot 

 blow the warm air away." The earth is being warmed every 

 day, all day, long. When the sun goes down, this heat 

 escapes from the ground. It warms the air next to the 

 ground. Now if we can cover the plarrts, t-his warm air 

 will be kept in, and so the plants will be saved. From what 

 does all this heat come ? Yes, it comes from the sun. 

 The sun is the source of heat. Do you think we could live 

 without the sun's heat ? No, every living thing would 

 perish. The sun gives us heat, and so it is the source of 

 life, too. How can we help warm plants and animals so 

 that they will thrive and increase for us ? Yes, by sheds, 

 walls, and protections against winds and cold. I saw 

 radishes in market last March. The frost was in the 

 ground. It was very cold, and the wind was blowing as it 

 always does in March. " They grew in a cold-frame or a 

 hotbed." " Perhaps they were raised in a greenhouse." 

 That is right. Let us see what you can tell me about these 

 things. These are the principal ways that we have of 



