Chapter VI: Well Boring at Great Depths (3)

The result of this arrangement is, that in the revolution of the crank the dead point of one of the levers is passed before that of the other is reached; so that the bucket which first comes to rest at the end of its stroke is started into motion again before the second bucket comes to rest. Thus in the lifting stroke of the bottom bucket worked by the upper lever K, the bucket in ascending has only reached the position shown at D in Fig. 220, at the moment when the top bucket worked by the lower lever H arrives at the bottom extremity of its stroke, and the bottom bucket D, which is still rising, continues to lift until it reaches its highest position, by which time the top bucket has got well into motion in its up stroke, and is in its turn lifting the water.