Hang the bell by its wire hook on the support rod in the bell jar.  Insert the bell power banana plugs in to the bell jar jacks.  Connect the 110 VAC power cord to the outside of the bell jar.

Connect the vacuum pump tubing to one of the bell jar valves. Close the bell jar valve on the other side.

Plug in the bell power cord.  The bell rings!

Put the bell jar on to its base. The bell will still be audible.

Switch on the vacuum pump and let it run for a minute or so.  Close the valve to the bell jar and switch off the vacuum pump.  No sound should be heard!

Open the valve on the opposite side of the bell jar and let air bleed in.  The sound of the ringing bell will return!