LABORATORY EXERCISES. 



2. What is the effect on the sheet lubber of re- 



moving air from within the jar? Explain. 



3. How is the toy balloon affected? Why? 



FIG. 5. 



B. Seize the marble tied into the sheet of rubber and 

 make the latter move up and down. 



1. Does the air within the bell- jar have more 



or less room when the rubber is pulled 

 down? 



2. Is the pressure within the glass jar now 



