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The ring being in effect a one-turn shorted secondary. A smaller ring will react even more violently. Here is another ring. This one made of a material we say is non-conductive, and it is completely unaffected. Here is another example. Several thousand watts of power were involved in that spark. If we replace the spark gap with a copper coil, the same power now flows through the coil. It's invisible, has no effect on many substances, but it can generate a lot of heat. Wood, paper, things that we think of as being quite inflammable, are not affected at all. However, a piece of steel wool bursts into flame instantly. Did you ever fry an egg on a coal stove? It's no trick at all, if you have the right equipment. This is a coal hot plate, and because it's coal, you can make it out of wood, if you like. Just be sure that there's a coil of wire inside, and that you connect that coil to a high voltage alternating current source. The rest is easy. As long as we're being different, we'll use motor oil instead of Crisco. The egg fries very quickly, but the stove remains perfectly cold. In fact, if you wish to keep it handy, you can fry your egg on the morning newspaper. With a gadget like this, you can get up in the morning, sit on the stove, read the morning newspaper, and fry the eggs in your lap. Another example of the fact that physical forces can be quite selective in their effect.