This is the way it was done back in the 1850s. It's undetectible and absolutely angle-proof. Ungimmicked bell may be passed out for examination, and is never handled by the spirit medium.
A hilarious routine comes with this amazing piece of comedy showmanship designed specifically for the sťance parlor or small stage, but it can actually be performed anywhere, even in daylight on the street, completely surrounded by spectators!!! It can also be performed "straight" without the comedy effect. Absolutely incredible vintage effect!
No wires, no magnets, no remote control, yet the bell rings every time, and is totally under YOUR control at every moment.