ELASTICITY OF AIR. 



Exhausting Syringe. Rate of Exhaustion. Impossible to produce a perfect Vacuum. Mechani- 

 cal Defects. The Air-Pump. Barometer Gauge. Siphon Gauge. Various Forms of Air- 

 Pump. Pump without Suction- Valve. Experiments with Air-Pump. Bladder burst by atmo- 

 spheric Pressure. Bladder burst by Elasticity of Air. Dried Fruit inflated by fixed Air. Flac- 

 cid Bladder swells by Expansion. Water raised by Elastic Force. A Pump cannot act in the 

 Absence of atmospheric Pressure. Suction ceases when this Pressure is removed. The Magde- 

 burg Hemisphere. Guinea and Feather Experiment. Cupping. Effervescing Liquors. 

 Sparkling of Champagne, dec. Presence of Air necessary for the Transmission of Sound. The 

 condensing Syringe. The Condenser. 



