The Fairies' Mint (Welsh Folk Tale)

Once upon a time there was a miller, who lived in Anglesey. One day he noticed that some of his sacks had been moved during the night. The following day he felt sure that some of his grain had been disturbed, and, lastly, he was sure someone had been working his mill in the night during his absence. He confided his suspicions to a friend, and they determined to go the next night and watch the mill. The following night, at about midnight, as they approached the mill, that stood on a bare stony hill, they were surprised to find the mill all lit up and at work, the great sails turning in the black night. Creeping up softly to a small window, the miller looked in, and saw a crowd of little men carrying small bags, and emptying them into the millstones. He could not see, however, what was in the bags, so he crept to another window, when he saw golden coins coming from the mill, from the place where the flour usually ran out.

Immediately the miller went to the mill door, and, putting his key into the lock, he unlocked the door; and as he did so the lights went out suddenly, and the mill stopped working. As he and his friend went into the dark mill they could hear sounds of people running about, but by the time they lit up the mill again there was nobody to be seen, but scattered all about the millstones and on the floor were cockle-shells.

After that, many persons who passed the mill at midnight said they saw the mill lit up and working; but the old miller left the fairies alone to coin their money.