Ducking (Dunking)
One 'foolproof' way to establish whether a suspect was a witch was ducking. With right thumb bound to left toe, the accused was plunged into a convenient pond. If he or she floated it proved an association with the black arts, with the body rejecting the baptismal water. If the victim drowned they were innocent. Given the curious position of the prisoner, it was more likely they would float.The second picture on the top is a example of ducking.
The Ducking Stool
The ducking stool or diving chair was a punishment which most often befell women prisoners. Grossly unpleasant, and often fatal, the woman would be strapped into a seat which hung from the end of a free-moving arm. The seat and the woman would be dunked into the local river or pond. The dunking could last for an entire day or just a few seconds. "It was up to the operators of the stool as to how long she remained under the water." Many elderly women were killed by the shock of the cold water. The first picture is a example of the device.