RAT-TRAP
The rat climbs a staircase to a trapdoor over a drowning tank.
The rat ascends an inclined, grooved runway toward a bait trough at the top of a water-filled tank. At the top it steps onto a pivoted platform held shut by an adjustable counterweight; the platform's far end is offset downward and joined by a steep incline, so the rat must pass over the pivot quickly. The rat's weight on the far end tips the platform and drops it into the water below, where it drowns. The counterweight then swings the door closed, resetting the trap for the next rat.
“It is necessary that the passage of the animal from the end 8 of the tilting door to the end 9 thereof be made quickly, since otherwise the tilting action of the door B might be so slow as to give the animal warning and enable it to avoid being dropped thereby into the interior of the casing or tank 1.”— Loui Pezzolo, from the specification
And the world did not beat a path to his door.