It was while he was in the Siberian prison camp that he came across a radio receiver powered by a kerosene lamp. He explained that the lamp had what is known as a thermopile which directly converts heat in to electricity. A thermopile is a mass of hundreds or thousands of thermocouple junctions in parallel and series to generate a useful amount of current. A thermocouple works due to the fact that when there is a junction of two dis-similar metals and there is a temperature difference a current flows.
I had no reason to disbelieve him or his amazing stories but for years I wondered if this thing really existed. For some reason after many years it suddenly popped in to my head and the wonders of the Internet let me research the subject. Sure enough there it was a kerosene lamp with a thermopile powering a transistor radio.
Visit this link to find out more.