The thought will naturally occur that by fostering belief in such tales as some of the foregoing, roguery might make the superstition useful in silencing inquiry as to ill-gotten gains. But on the other hand the virtues of hospitality and generosity were no doubt fostered by the same influences. If any one was favoured by the fairies in this manner, the immediate explanation was, that he had done a good turn to them, generally without suspecting who they were. The virtues of neatness, in young girls and servants, were encouraged by the like notions; the belief that a fairy will leave money only on a clean-kept hob, could tend to nothing more directly. It was also made a condition of pleasing the Tylwyth Teg that the hearth should be carefully swept and the pails left full of water. Then the fairies would come at midnight, continue their revels till daybreak, sing the well-known strain of 'Toriad y Dydd,' or 'The Dawn,' leave a piece of money on the hob, and disappear. Here is seen a precaution against fire in the clean-swept hearth and the provision of filled water-pails. That the promised reward did not always arrive, was not evidence it would never arrive; and so the virtue of perseverance was also fostered.