Once upon a time the king of a far country was sitting on his throne, listening to the complaints of his people, and judging between them. That morning there had been fewer cases than usual to deal with, and the king was about to rise and go into his gardens, when a sudden stir was heard outside, and the lord high chamberlain entered, and inquired if his majesty would be graciously pleased to receive the ambassador of a powerful emperor who lived in the east, and was greatly feared by the neighbouring sovereigns. The king, who stood as much in dread of him as the rest, gave orders that the envoy should be admitted at once, and that a banquet should be prepared in his honour. Then he settled himself again on his throne, wondering what the envoy had to say.

The envoy said nothing. He advanced to the throne where the king was awaiting him, and stooping down, traced on the floor with a rod which he held in his hand a black circle all round it. Then he sat down on a seat that was near, and took no further notice of anyone.

The king and his courtiers were equally mystified and enraged at this strange behaviour, but the envoy sat as calm and still as an image, and it soon became plain that they would get no explanation from him. The ministers were hastily summoned to a council, but not one of them could throw any light upon the subject. This made the king more angry than ever, and he told them that unless before sunset they could find someone capable of solving the mystery he would hang them all.

The king was, as the ministers knew, a man of his word; and they quickly mapped out the city into districts, so that they might visit house by house, and question the occupants as to whether they could fathom the action of the ambassador. Most of them received no reply except a puzzled stare; but, luckily, one of them was more observant than the rest, and on entering an empty cottage where a swing was swinging of itself, he began to think it might be worth while for him to see the owner. Opening a door leading into another room, he found a second swing, swinging gently like the first, and from the window he beheld a patch of corn, and a willow which moved perpetually without any wind, in order to frighten away the sparrows. Feeling more and more curious, he descended the stairs and found himself in a large light workshop in which was seated a weaver at his loom. But all the weaver did was to guide his threads, for the machine that he had invented to set in motion the swings and the willow pole made the loom work.

When he saw the great wheel standing in the corner, and had guessed the use of it, the merchant heaved a sigh of relief. At any rate, if the weaver could not guess the riddle, he at least mig............