" Churchill warned them now: “When you are drifting down the stream of Niagara, it may easily happen that from time to time you run into a reach of quite smooth water, or that a bend in the river or a change in the wind may make the roar of the falls seem far more distant. But”—his voice dropped a register, and only those who strained could hear—“your hazard and your preoccupation are in no way affected thereby. "

― William Manchester , The Last Lion: Winston Spencer Churchill: Alone, 1932-40