My grandfather’s lamp, suspended by its hook, hung from a nail driven high into the wall in our outside lavatory. It was so familiar a sight for me as a child that I ceased to notice it. When the house in Gilfach Goch was cleared ahead of sale it was one of the items I bore away. Even then I gave it little attention. Many years passed before its significance and worth dawned upon me. I treasure it now as a twofold connection with the past, one personal, as an object contributing to the story of my family, the other general, as an artefact recovered from the history of the South Wales coalfield.

It is an overman’s lamp, somewhat smaller than those one sometimes sees in bric-a-brac shops, and made entirely of brass rather than the more usual steel and brass. It is intact, even to the wick, after a hundred years or so, though dented (wounded if you like). Sometime during its working life a heavy weight has fallen on it with force enough to fracture the circular boss at the top and drive it downwards a millimetre or two. The broken metal has been soldered in the blacksmith’s shop (every colliery had a blacksmith’s shop), but this scarred lid and the ring of perforations immediately below it remain buckled.

At intervals, I have taken a rag and a tin of Brasso and brought up the shine on it, but over the years an unsightly white deposit has built up in inaccessible folds and joints. Recently I tried submerging the lamp in ...