We were never at all deceived as to what would be the purpose of such a visit after our entrance into the war. In the early part of 1917 the Allies believed that a few German U-boats might assail our coast, and I so informed the Navy Department at Washington. My cables and letters of 1917 explained fully the reasons why Germany might indulge in such a gesture. Strategically, as these despatches make clear, such attacks would have no great military value. To have sent a sufficient number of submarines to do any considerable damage on the American coast would have been a great mistake. Germany's one chance of winning the war with the submarine weapon was to destroy shipping to such an extent that the communications of the Allies with the outside world, and especially with the United States, would be cut. The only places where the submarine warfare could be conducted with some chance of success were the ocean passage routes which lead to European ports, especially in that area south and south-west of Ireland in which were focussed the trade routes for ships sailing from all parts of the world and destined for British and French ports. With the number of submarines available, the Germans could keep enough of their U-boats at work in these areas to destroy a large number of merchant ships. Germany thus needed to concentrate all of her available submarines at these points; she had an inadequate number for her purpose; to send any considerable force three thousand miles across the Atlantic would simply weaken her efforts in the real scene of warfare and would make her submarine campaign a failure. The cruises of submarines on the American coast would have been very much longer and would have been a much more serious strain on the submarines than were the shorter cruises in the inshore waters of Europe. As has already been explained, the submarine did not differ from other craft in its need for constant repairs and careful upkeep, except that perhaps it was a more delicate instrument of warfare than any other naval craft, and that it would require longer and more frequent periods of overhaul. Any operations carried out three thousand miles from their bases, where alone supplies, spare parts, and repair facilities were available, would have soon reduced the submarine campaign to comparative uselessness; each voyage would have resulted in sinking a relatively small amount of shipping; a great number of submarines would be out of commission at all times for repairs, or would be lost through accidents. The Germans had no submarine bases in American waters and could establish none. Possibly, as the newspaper writer has pointed out, they might have seized a deserted island off the coast of Maine or in the Caribbean, and cached there a reservoir of fuel and food; unless, however, they could also have created at these places adequate facilities for repairing submarines or supplying them with torpedoes and ammunition, such a place