This model demonstrates the functioning of one of the most spectacular apparatus produced by ancient pneumatics. Described by Hero in his Pneumatics, this device consists of an altar on which is set a branch with fake birds. Water is poured into the top cup and conveyed through pipe T to the recipient at the bottom R, from which it emerges forcing the air to rise in pipe U. At this point, the same air "bounces" on the surface of the water in recipient V and enters pipe Z, passing through the fake branch, entering the bird's body and ending in a whistle, or rather a bottleneck that generates a whistling sound that imitates a twitter. These mechanical wonders were already in vogue in Alexandria in the 3rd century BC, when Archimedes stayed in the Egyptian city.