Mystery Solved

Last week, I encountered a tower while walking through the woods. Today, I passed the same tower and went off the path to investigate. A peek into the dilapidated hut at its base revealed an abandoned well. The tower was for a windmill used to pump water for irrigation. A follower of this blog suspected as much and can take credit for solving the puzzle. As a prize for that bit of sleuthing, I am offering a new challenge based on an object I found later on the same walk. I know this mystery will be of special interest because this individual is a subject matter expert on gears.