if Cleopatra's nose had been shorter, the whole face of the world might have been changed, and Voltaire is never tired of dwelling on the small springs on which the greatest events of history turn. Frederick the Great, who was probably the keenest practical intellect of his age, constantly insisted on the same view. In the vast field of politics, he maintained, casual events which no human sagacity can predict play by far the largest part. We are in most cases groping our way blindly in the dark. Occasionally, when favourable circumstances occur, there is a gleam of light of which the skilful avail themselves. All the rest is uncertainty. The world is mainly governed by a multitude of secondary, obscure, or impenetrable causes. It is a game of chance in which
