The Piskie Threshers
Here is an interesting story from Couch via Hunt of a farmer who discovers that a piskie is helping him by threshing his wheat at night. The man gives the piskie a new set of clothes the next night in gratitude, with a surprising result:
Many an industrious farmer can speak of the assistance which he has received from the piskies. Mr T. Q. Couch tells a story of this kind so well that no other is required. Long long ago, before threshing–machines were thought of, the farmer who resided at C—, in going to his barn one day, was surprised at the extraordinary quantity of corn that had been threshed the previous night, as well as to discover the mysterious agency by which it was effected. His curiosity led him to inquire into the matter; so at night, when the moon was up, he crept stealthily to the barn–door, and looking through a chink, saw a little fellow, clad in a tattered suit of green, wielding the "dreshel" with astonishing vigour, and beating the floor with blows so rapid that the eye could not follow the motion of the implement. The farmer slunk away unperceived and went to bed, where he lay a long while awake thinking in what way he could best show his gratitude to the piskie for such an important service. He came to the conclusion at length, that, as the little fellow’s clothes were getting very old and ragged, the gift of new suit would be a proper way to lessen the obligation; and, accordingly on the morrow he had a suit of green made, of what was supposed to be the proper size which he carried early in the evening to the barn, and left for the piskie’s acceptance. At night the farmer stole to the door again to see how his gift was taken. He was just in time to see the elf put on the suit, which was no sooner accomplished than, looking down on himself admiringly, he sung–
Piskie fine, and piskie gay,
Piskie now will fly away.
Margaret Ann Courtney adds a comment fitting to this story:
Should the happy possessor of one of those industrious, unpaid fairy servants (who never object to taking food left for them by friends) express his thanks aloud, thus showing that he sees him, or try to reward him for his services by giving him a new suit of clothes, he leaves the house never to return, and in the latter case may be heard to say:
Pisky fine, piskie gay,
Pisky now will fly away.
Or in another version:
Pisky new coat, pisky new hood,
Pisky now will do no more good.
The law of unintended consequences strikes here as the piskie flies away when given new clothes.
Courtney adds to this that 19thC Cornish believed that thanking a piskie, or giving him new clothes, meant the piskie was recognized by a mortal and would fly away.
J K Rowling has it that giving new clothes to an elf by his master frees the elf, and the elf will be free to leave.
Finally, this story is the inspiration to put a non-Cornish folktale, Rumpelstiltskin, on Gandolf dot com.