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Cut off an ordinary candle on both sides so that you get to the wick. Stick a heated knitting needle in the middle of the length. Put the candle horizontal and put ends of a needle which stretch out of the candle on two glasses. When we light up both wicks, the candle starts to swing. When a drop of wax falls down on one side, the candle looses its balance and preponderates to the other side. There the flame grazes the candle, so that a drop of wax falls down also on this side. Candl