On May 25, 1917, Admiral Sims cabled to Secretary Daniels that Berlin knew of American plans for sending our destroyers to Europe four days before the vessels arrived at Queenstown, and that twelve mines had been placed across the entrance to the harbor the day before the destroyer flotilla reached their destination. The activity of British mine-sweepers prevented whatever might have occurred. This gave rise to considerable discussion in this country as to German spies here, and as an instance of their work in keeping in touch with naval affairs the following story was told in naval circles: When the oil-ship _Vacuum_, with Lieutenant Thomas and a naval gun crew on board, sailed from this country, the captain had instructions where to pick up British destroyers at a certain point off the Irish coast. The _Vacuum_ arrived at the designated spot, and before the war-ships arrived a submarine appeared out of the water. "I see," said the German commander, appearing out of the conning-tower, "that you kept your appointment." And then the _Vacuum_ was sent to the bottom. Later, under the convoy system, submarines began to be very wary in the matter of triumphant conversations with officers of merchantmen. In fact, this appears to have been the last interchange of the sort. Working with the British, the American destroyers patrolled the seas six days at a stretch, each craft being assigned to a certain area, as far out as three hundred miles off shore. Returning to port, the destroyers would lie at their moorings two and three days. Later the time in port was reduced. But it depended upon conditions. The orders to the Americans were: first, destroy submarines; second, escort and convoy merchant ships; third, save lives. And in all three respects the Americans from the very outset have so conducted themselves and their craft as to earn the highest encomiums from the Entente admiralties. The Americans entered very heartily into their work, and developed ideas of their own, some of which the British were very glad to adopt. Between the men of the two navies there has been the best sort of feeling. CHAPTER V British and American Destroyers Operating Hand in Hand--Arrival of Naval Collier "Jupiter"--Successful Trip of Transports Bearing United States Soldiers Convoyed by Naval Vessels--Attack on Transports Warded Off by Destroyers--Secretary Baker Thanks Secretary Daniels--Visit to our Destroyer Base--Attitude of Officers Toward Men--Genesis of the Submarine--The Confederate Submarine "Hunley"