Chapter 12, Part 11A - Chuang Tzu

Tzu-kung traveled south to Ch'u, and on his way back through Chin, as he passed along the south bank of the Han, he saw an old man preparing his fields for planting. He had hollowed out an opening by which he entered the well and from which he emerged, lugging a pitcher, which he carried out to water the fields. Grunting and puffing, he used up a great deal of energy and produced very little result.

"There is a machine for this sort of thing," said Tzu-kung. "In one day it can water a hundred fields, demanding very little effort and producing excellent results. Wouldn't you like one?”

The gardener raised his head and looked at Tzu-kung. "How does it work?"

"It's a contraption made by shaping a piece of wood. The back end is heavy and the front end light and it raises the water as though it were pouring it out, so fast that it seems to boil right over! It's called a well sweep."
~ Burton Watson translation via Terebess Asia Online ~

Go here to read the introductory post to the chapters of the Book of Chuang Tzu.