Another American pilot managed the rare feat of dropping a bomb precisely upon the centre of the deck of a submarine, and had the unhappy experience of seeing it fail to explode--as recently happened in the submarine fight off Cape Cod, near Chatham. In hunting for the submarines the American destroyers have patrolled an area as wide as that bounded roughly by the great V formed by New York, Detroit, and Knoxville, Tenn. And while patrolling they have become skilled in the use of the depth charges, in establishing smoke screens so as to hide vessels of a convoy from the periscope eye, and in marksmanship. One gun crew not long ago saw the spar of a sunken ship which they at first took to be a periscope. They shattered that spar at a distance of 2,000 yards--more than a mile. Filled with the enthusiasm of each new encounter with the enemy, the Americans have not been slow to build upon their experience, devising more effective methods against the next affray. For example, two officers working on designs for new destroyers have introduced many new ideas gained from their experiences in submarine-hunting. Suggestions relating to improved gun-fire and the like are always arising from the men of the fleet, and often they are accepted and applied. A new appliance--I don't know by whom invented--is an improved microphone, by which the revolutions of a propeller are not only heard, but the direction also is indicated, while the force of the under-water sound-waves are translated on an indicator in terms of proximity. The great drawback to this is that the submarines are also equipped with microphones of the sort--or at least are said to be. It is usually a grim business on both sides; but occasionally a bit of humor comes out of the seas. A case in point was the message received almost every night by an American destroyer in European waters. The radiogram said: "My position is ---- degrees north, and ---- degrees west. Come and get me; I am waiting for you." "HANS ROSE." Now Hans Rose was the name of the German submarine commander who visited Newport, October, 1917, as we have already narrated. Twice the destroyer proceeded swiftly to the location, but never did Hans Rose keep his appointment. If he had the American sailors would not have given Captain Rose's crew beer upon that occasion, as they did when Rose and his U-boat dropped into Newport harbor.