The Mousetrap

When we moved to Ballybrack I was just about to head into my teens, and I was full of curiosity.

Imagine my delight to find a very strange object in a stairway cupboard, left behind by the previous occupants. It was a sort of tin in a wooden frame with rectangular bit sticking out at the bottom. It was about a foot high and the rectangular bit was about 6 inches long. It didn't take me long to figure out that it was a self-resetting mousetrap. A really beautiful piece of work.

Many times since, I have tried to explain how it worked to friends and acquaintances only to leave them as mystified when I'd finished as before I'd started.

So here is the definitive illustrated version.

The mouse enters the rectangular compartment, from the left, to have a go at the cheese, on the right of the compartment.

As he passes the midpoint, the floor, which is on a pivot, tilts to the right. This closes the door behind him, and, incidentally, resets the platform at the top of the can back into the horizontal position.

Unfortunately for him, the cheese is behind a grill so he can't get at it. And the only way out is up. As he climbs up the passage, he passes through a gravity trap, which he can push out of the way as he goes up, but which is then closed to him, cutting off his "escape" back down.

So the only way to go is further up and walk the plank, so to speak. His weight on the plank pivots it down and he falls in the water and drowns. Meanwhile the pivoting of the plank has reset the door to open, ready for the next mouse.

QED

Bet you thought this was going to be a literary post.

Required legal notice:
No real mice have been harmed in the cutting off of the mouse's tail in Photoshop.