this was part of a broader fear of spirits that might flit into dwellings. witch bottles were common throughout europe – bottles or glass spheres containing a mass of threads, often with charms entangled in them. its purpose was to draw in and trap evil and negative energy directed at its owner. folk magic contends that the witch bottle protects against evil spirits and magical attack, and counteracts spells cast by witches, also forestalling the passage into habitations of witches flying about at night. a witch ball was much the same; however, a more light-hearted belief was that the witch saw her distorted face in the curved glass and was frightened away. the term witch ball is probably a corruption of "watch ball" because it was used as a guard against evil spirits.