The Germans, naval officers pointed out, might well conclude as soon as we declared war to send submarines across the Atlantic to attack shipping and cut down the flow of munitions and supplies to Europe. One or two operating in the Gulf might interrupt the shipment of oil from Mexican fields, the largest source of supply for the British Fleet. A strong patrol force would not only protect all shipping on this side of the ocean, but, well organized and equipped, would be ready when called upon, to operate in European waters, as it did later on. So, it was determined to assign Wilson to that duty and Admiral William S. Sims was then chosen for the London mission. On Monday, March 26, I telegraphed him to come to Washington. He arrived on the 28th and came to the Navy Department in the afternoon. Referring to Mr. Page's telegram, I told him the President had decided to send an admiral to England, and he had been selected. Informing him, in confidence, of our belief that the time was near at hand when the United States would enter the war, I told him that, in that event, we must prepare for the fullest coöperation with the British Navy. But his immediate duty, I pointed out, was to secure all possible information as to what the British were doing, and what plans they had for more effective warfare against the submarines. In the course of the conversation, I said: "You have been selected for this mission not because of your Guildhall speech, but in spite of it." In that speech Sims had said, "If the time ever comes when the British Empire is seriously menaced by an external enemy, it is my opinion that you may count upon every man, every dollar, every drop of blood of your kindred across the sea." Impressing upon him the fact that the United States was still neutral, and that until Congress should declare war his mission must be a secret and confidential one, I informed him that it had been decided not to issue written orders detaching him from his duties at Newport, but for him to go quietly as a civilian passenger, and report to Ambassador Page personally before any public announcement was made. Among the matters discussed was the extent of the sinkings by submarines. Ambassador Page had written me confidentially that the situation was more serious than the British admitted. I told Admiral Sims that the President believed the British had not taken the necessary vigorous offensive to prevent destruction of shipping by the U-boats and that he strongly believed two things ought to be done: First, that every effort should be made to prevent the submarines getting into the Atlantic--that they ought to be shut up in their own coasts, or some method should be found to prevent their ingress and egress.