User talk:51.6.92.81

We faced real difficulties in London during the great smog. I was only a boy at the time, but I remember very clearly an experiment I performed (at home because travel to school was impossible). I stood outside the back door of our house in Friern Barnet, North London, at twelve noon. I held up my hand in front of my face, in a comfortably natural position with palm towards me at a distance of about a foot from my eyes, and I could not see my hand at all. It was completely obscured by the thick yellow smog.