No Trappers Needed

In the bad old days of coal mining, there were lots of dangerous, unpleasant, and boring jobs. Ventilating airflow produced by large fans was directed by strategically placed doors in the labyrinth of underground tunnels. The people -- usually young children -- who were employed to open and close these doors to allow passage of coal cars, were called trappers. They sat or stood in total darkness while waiting for traffic. Often the ground would be wet, and rats were common.

I can't help thinking about this when I open and close the gate valves on my duct collection system in my warm, brightly lit workshop. My grandparents were very glad I didn't have to work in the mines!