Neidpath Tunnel

As thebear was safely out of the way at work I was able to walk through this old railway tunnel this morning.  It's 600 yards long but surprising clean inside. When checking its history I discovered this interesting fact...

In the early part of the 20th century, Nobel Prize winning scientist C T R Wilson used the tunnel - after traffic had ceased for the night - to conduct experiments with his cloud chamber to prove (or not) the existence of cosmic radiation.