ELECTRICAL RODENT EXTERMINATOR
Electrocutes the mouse for ten seconds, then stops to prevent charring.
The mouse enters through the open front of the casing and pushes a swinging baffle while moving toward the bait. The baffle pivots a rod that closes a magnet-held trip switch, starting a clock timer. The timer feeds current from a transformer, stepped up to approximately 480 volts, into a pair of oppositely charged grids on the floor. The mouse standing on the grids completes the circuit and is electrocuted; after about ten seconds the timer cuts the current, and a red signal lamp remains lit to indicate a catch.
“This device could perhaps operate satisfactorily with a single rodent, but once the animal died, the continuing electrical charge would cause charring of the carcass and would thus frighten off any additional rodents.”— Irvin Levine, from the specification
And the world did not beat a path to his door.