how does the duck describe the movement of the kangaroo ?

The Duck is fascinated by the movement of the Kangaroo. He marvels at the Kangaroo's ability to hop over waters and fields, an idea which he later on extends to the idea of hopping over seas and lands. He feels that the Kangaroo's hopping could never be stopped which suggests incessant change of place, which in turn is something that the Duck desires as he wants to go round the world.