EXPERIMENTS WITH FLOWERS 223 



Method. Note first that there is nothing but air in the 

 bottles. Place the flowers in one bottle and cork tightly 

 for ten or twelve hours. Remove the cork and test the gas 

 with a burning stick, with limewater, etc., to determine 

 whether it is oxygen or carbon dioxide. Test the contents 

 of the other bottle which has been corked and kept as a 

 control. Result? 



Conclusion. State what is given off by flowers. 



190. FLOWERS GIVE OFF HEAT 



Object. To demonstrate the evolution of heat by 

 flowers. 



Apparatus. Fresh flowers of dandelion, aster, elder, a wide- 

 mouth bottle, perforated cork, thermometer, sealing wax or par- 

 affin. 



Method. Fill the bottle loosely with the flowers. Pass 

 the thermometer through the cork and insert it in the bottle. 

 Close the opening with wax to prevent escape of air and set 

 it away for observation. Watch the thermometer. Does 

 the temperature rise or fall ? How can this be accounted for ? 

 In what way is the result of this exercise connected with that 

 of the preceding Experiment? 



Conclusion. State the result of your observations. 



