lO 



at the top.) Place a couple of pencils beside the relighted can- 

 dle and on them the chimney, as in Fig. i6. 



Qnes. What is the difference between the way in which the 

 candle burns now and before the chimney was placed over it ? 



Alls. It flickers, or dances about more. 



Ques. What makes boys and girls feel like dancing about 

 when thev o"o out from a warm school room ? 



Ans. The fresh air. 



Qties. What makes the flame dance 

 or flicker when the chimney is raised by 

 the pencils ? 



Ans. Because it P'ets fresh air under 

 the chimney. 



Repeat the first experiment, in which 

 the flame grows gradually smaller till it 

 is extinguished. 



Qiies. Why now does the flame die out? 



Ans. Because it had no fresh air. 



Qiies. Is it really necessary to have 

 fresh air in order to keep a flame burning? 



Ans. Yes ; since otherwise the can- 

 dle would continue to burn until it is all 

 used up. 



To prove this further, let the 

 candle be relighted. Place the 

 chimney over it, now having 



the top completely closed by a i6. supplying air underneath the chimney. 



piece of paper. Have ready a lighted splinter or match, and 



piece of white crockery or window glass, a piece of fine wire about six inches long, 

 a bit of quicklime about half the size of an egg, and some matches. All of these, 

 with the possible exception of the quicklime, can be obtained in any household. 

 If you perform the experiment requiring the lime, be sure that you start with a fresh 

 piece of quick or stone lime, which can be had of any lime or cement dealer. Dur- 

 ing the performance of the following simple experiments, ask your pupils to describe 

 to you what they see you do at each step. The questions inserted in the text are 

 ofTcred merely as suggestions in the developing of the desired ideas. The answers, 

 which are intended only for the teacher, are those which it is desired shall be given 

 by the pupils. 



