I have watched the French Emperor narrowly, and have studied his character and conduct. You may rely upon it that, at the bottom of his heart, there rankles a deep and inextinguishable desire to humble and punish England, and to avenge, if he can, the many humiliations — political, naval and military — which, since the beginning of this century, England has by herself and her allies inflicted upon France. He has sufficiently organised his military means; he is now stealthily but steadily organising his naval means; and when all is ready, the overture will be played, the curtain will draw up, and we shall have a very disagreeable melodrama.

Letter to the Duke of Somerset (23 June 1861), quoted in Lord Dalling, Life of Palmerston: Volume II, p. 391.