sinful origin Some legends say that selkies could turn human every so often when the conditions of the tides were correct, but oral storytellers disagreed as to the time interval. In Ursilla's rumour, the contacted male selkie promised to visit her at the "seventh stream" or springtide. In the ballad The Great Silkie of Sule Skerry, the seal-husband promised to return in seven years; the number "seven" being commonplace in balladry. According to one version, the selkie could only assume human form once every seven years because they are bodies that house condemned souls. There is the notion that they are either humans who had committed sinful wrongdoing, or fallen angels. Superstitions It was only during hard times that the people of the Scottish Isles would kill seals to make use of their skin and blubber. It was thought that the killing of a seal would result in misfortune for the perpetrator. Ernest Marwick recounts the tale of crofters who brought their sheep to graze upon a small group of holms within the Orkney Islands. During the summer, a man placed seven sheep on the largest holm. While on his way home from grazing sheep, the man killed a seal. That night, all of the man's sheep disappeared, however, the other crofters, who had not killed a seal, did not lose their sheep. Orkney tales The selkie-wife tale had its version for practically every island of Orkney according to W. Traill Dennison. In his study, he included a version collected from a resident of North Ronaldsay, in which a "goodman of Wastness", a confirmed bachelor, falls in love with a damsel among the selkie-folk, whose skin he captures. She searches the house in his absence, and finds her seal-skin thanks to her youngest daughter who had once seen it being hidden under the roof. In "Selkie Wife", a version from Deerness on the Mainland, Orkney, the husband locked away the seal-skin in a sea-kist (chest) and hid the key, but the seal woman is said to have acquiesced to the concealment, saying it was "better tae keep her selkie days oot o' her mind". However, when she discovered her skin, she departed hastily leaving her clothes all scattered about. A fisherman named Alick supposedly gained a wife by stealing the seal-skin of a selkie, in a tale told by an Orkney skipper. The Alick in the tale is given as