Yank or Yanking my chain. I heard just the other day on the History Channel someone discribing the origin of this phrase being the gold mines in places like Colorado. When a miner would use the "toilet" (one of the mining wagons on the rails but with a wooden top on it and a hole) he would place a chain under the wheel of the rail car because his fellow miners might play a prank on him and push him down the rail way while he was using the toilet. So the miner who was trying to relieve himself would declare "don't yank my chain". Any truth to this? I wonder if rattling someone's cage has to do with mining also?