Experiment 22. Effect of increased pres- 

 sure upon the temperature of boiling. 

 c. Boiling temperature lowered by reduced 

 pressure. , 



Experiment 23. Effect of decreased 

 pressure upon the temperature of bcil- 

 ing. 



21. Sublimation a change from solid to gas. 



Experiment 24. Two kinds of sublinn- 

 tion. 



22. Frost and snow. 



Experiment 25. Imitation frost. 



23. Special forms of combustion. 



a. Deflagration. 



Experiment 26. Examples of deflagra- 

 tion. 



b. Explosions. (See Sections 85 and 87.) 



Experiment 27. Examples of explosions. 



24. Physical changes. 



a. Due to heat. 



Experiment 28. Effect of heat upon 

 conditions of matter. 



b. Due to dampness. 



Experiment 29. Sympathetic ink. 



25. Heat from compression. 



Experiment 30. Heat due to compress- 

 ion. 



26. Chemical changes. 



a. In air and in solution. 



Experiment 31. Examples of chemical 

 changes. 



b. Due to heat. 



Experiment 32. Heat aids chemical 

 changes. 



