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

 cal Defects. — The Air-Pump.— Barometer Gauge.— Siphon Gange. — 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, &c— Presence of Air necessary for the Transmission of Sound.— The 

 condensing Syringe.— The Condenser. 



