CARBON DIOXIDE 123 



Since animals inhale oxygen and exhale carbon dioxide, it 

 is seen how nice is the balance between animal life and vege- 

 table life. 



References : 



1. 1103:8-9. Carbon Dioxide. 



2. 1304 : 336. Importance of Carbon Dioxide to Plants. 



3. 1407 : 107-108. Effects of Carbon Dioxide on Plants. 



4. 1702 : 66-68. Carbon Dioxide in Air. 



5. 1703 : 112-113. Carbon Dioxide in the Atmosphere. 



6. 1710 : 9-10. Sources and Amount of Carbon Dioxide. 

 a. 1302 : 274-275. Carbon Dioxide in Air. 



6. 1612 : 45-46. Carbon Secured by the Leaves from Car- 

 bon Dioxide. 



c. 1706 : 193-194. Properties of Carbon Dioxide and its Re- 



lation to Life. 



d. 1707 : 189-196. Chemical Properties of Carbon Dioxide ; 



Respiration. 



e. 1707 : 196-198. The Cycle of Carbon in Nature. 



Experiment 48. Sources of Carbon Dioxide. 



Apparatus: Funnel, syringe bulb with inlet and outlet 

 tubes, glass tube \" diameter, 8" long, test tube 8" X I", ring 

 stand. 



Materials: Limewater, candle. 



a. Place bulb between funnel and glass tube, put candle 

 under mouth of inverted funnel, and insert glass tube in test 

 tube containing 5 c.c. limewater. Light candle. Gently 

 force the air from the funnel into the limewater, and note 

 how quickly it becomes milky. 



b. Remove candle, take the apparatus to an open window, 

 and repeat process (without candle) with fresh and clean 

 limewater. What are your conclusions ? 



c. Remove funnel and gently breathe into some fresh lime- 

 water. What must you conclude ? 



