You can't see the turbine because it's inside the chimney.

When the hot air from the fire rises, the turbine turns around.

The turbine is connected by a shaft to the spit.

This is a drawing of a heat powered spit done by Leonardo da Vinci in 1480. The turbine is at the top.

Leonardo da Vinci is one of the first people to put this idea down on paper but he may have got it from Tartar slaves who came to Italy in the fifteenth century.

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