Going back to the original post:

My late first wife told me that as a child she used to watch dancing lights, pinhead size, in a corner of a room, down near the skirting board in the first house she lived in, in Suffolk. She assumed that they were what people called faries.

On the day that her father died we went down to the beach for a late evening stroll. As the waves came in they began to flash along their length just before they broke, in the vertical wall of water. It was phosphorescence caused by millions of tiny organisms. Imagine 10 yard long green flourecent lights.

Robin