TRAP
A float-suspended elevator lowers each mouse to a holding cage.
The mouse enters a chamber that hangs from a float riding in a fluid-filled upper compartment. When the mouse steps on the baited treadle, a latch releases and the chamber, now too heavy for the float to sustain, sinks in the lower compartment, closing the entrance and bringing an exit opening into registry with a wire cage. The mouse passes through a conical screen guard into the cage. The emptied chamber is lightened, the float raises it back to the set position, and the latch re-secures it for the next animal.
“The present invention relates to new and useful improvements in traps particularly for rats and mice and has for its primary object to provide, in a manner as hereinafter set forth, a device of this character comprising novel float operated means for automatically resetting itself after imprisoning the animal.”— John C. Russell, from the specification
And the world did not beat a path to his door.