When this message was received by the Atlantic Fleet, at 1:33 p. m., Admiral Henry T. Mayo, Commander-in-Chief, hoisted on his flagship, the _Pennsylvania_, the signal, "War has commenced." At 5:50 o'clock he received the mobilization order, for which officers and vessels were so well prepared that Admiral Mayo said he did not have to "give a single order of any kind or description to pass the Fleet from a peace to a war basis." The entire Navy--Department, Fleet, yards and stations--was on a war footing within a few hours after war was declared. Complete instructions and plans, brought up to date, had been issued two weeks previous, and mobilization was completed without an hour's delay. The Fleet was at its secret rendezvous "Base 2," to which it had sailed from Hampton Roads on April 3, the day after President Wilson delivered his war message to Congress. "Base 2" was Yorktown, Va., one of the most historic spots in America, and our battleships were in sight of the place where Cornwallis surrendered to George Washington. They rode at anchor in the waters where the timely arrival of De Grasse's ships assured the success of the war for American independence. In those waters, first made historic in naval annals by the presence of the French ships sent to aid the struggling colonists in the crucial days of 1781, the American Navy was making ready to repay that invaluable assistance--to send its vessels to the beleaguered French coast, both to safeguard the vast army America would send to France and to drive back the onrushing enemies that threatened its life. In 1917 the York and the Chesapeake were again the rendezvous of fighting men of the same mettle as those of 1781, who were to strengthen by united service and common sacrifice in the World War the bonds of friendship between France and America that had been forged more than a century before. And those who fought each other then were comrades now. "Old wars forgot," Great Britain and France for years had held the lines, and America was taking its place beside them, throwing all its power and strength with them against the common foe. From Yorktown went the first United States forces, ordered overseas just after war began. Sent to England's aid, to serve with the British forces, their arrival was hailed as the beginning of a new era in the relations of the nations--the "Return of the Mayflower." And later went huge dreadnaughts to the North Sea, joining the Grand Fleet in the mightiest aggregation of naval power the world has ever seen. That is a wonderful harbor, there in the York River, with water deep enough for the largest battleship, and broad enough to accommodate a whole fleet. With defenses at the entrance to Chesapeake Bay, and nets, mines and patrol across York River, no submarine could ever hope to penetrate to this safe haven.