When Newton saw an apple fall, he found In that slight startle from his contemplation- 'Tis said (for I'll not answer above ground For any sage's creed or calculation)- A mode of proving that the earth turn'd round In a most natural whirl, called 'gravitation'; And this is the sole mortal who could grapple, Since Adam, with a fall, or with an apple.

DON JUAN (ed. 1875)