Suppose [he said to the Americans] that it was a familiar thought in your minds that there never was at any moment of the year within the limits of your State more than seven weeks food for the population, and that that food had to be replenished by overseas communication...Then you will understand why every citizen of the British Empire, whether he comes from the far Dominions of the Pacific, or the small island in the North Sea, can never forget...that without sea communication he, and the Empire to which he belongs, would perish.