We have just been for a walk, down in the Torrs, in New Mills. We were leaning on the parapet of the bridge by Torr Mill, watching the river, when we began a conversation with a friendly woman passing by with her dog. After answering her question about the footpath closure because of the dangerous condition of the rock-face, I mentioned our new information display outside the Heritage Centre.
At once, she proudly told us that her grandson was the young boy mentioned on the new sign on the nearby handrail: the boy who discovered that it works as a speaking tube.
I told her that I was the person who put the sign there, after seeing her grandson shout into it as he walked past with his father and brother.
It further emerged that she lives right next to the location of my next local 'guerilla science-communication' project, at Chain Horse House, where I'm planning to hang another sign drawing attention to 300-million-years-old water-ripple-marks in the stone paving slabs.