Light falling on to this layer creates an electric charge.

ECONOMIST: Curtains for celluloid

Under the glare of electric lights, I saw that the porcelain was coated with a layer of dust, the silverware dulled by tarnish.

NEWYORKER: Sweetheart Sorrow

Stick the part in acid, run an electric current through it and we can increase the thickness of the layer by a factor of 20-40.

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