The system followed now in the locating and possible destruction of German submarines in the Channel and North Sea by French dirigibles is as follows: The airships, chiefly of the _Astra_ type, travel at a height of not more than 500 feet above the surface of the ocean, while the observers constantly sweep the water within a radius of half a mile with their glasses. Usually the airships are sent ahead at low speed in spirals, or in a series of curves which enable them to cover every square mile of watery area below. As soon as one of these airships sights a submarine traveling submerged, it flashes the news by wireless to destroyers which at the time may be fifty or more miles away, and in the meantime endeavors to remain directly above the submerged boat. Soon the destroyers arrive and, following the direction of the airship, can ram or sink the submarine with almost certain success. The French admiralty claims to have accounted for a number of submarines by this method, but has found that the scheme no longer will work. The German naval department, learning of the airship patrol, has given its submarine commanders orders to travel at great depth during daylight hours in the Channel and the southwestern section of the North Sea, or to go to sleep on the bottom where the sea is too shallow. In the evening the boat makes its escape from the dangerous neighborhood. The third field of action of airships--devastating hostile countries--is the least valuable, although perhaps the most spectacular of the activities of airships of the Zeppelin type. The damage caused by the numerous Zeppelin raids over England, for instance, is a subject of so much dispute that a true appreciation of their value cannot be formed at present. While the German official bulletins repeatedly declare that great material damage was done by the bombs to military establishments, factories, harbor works, etc., the British statements dwell more upon the number of noncombatants who were killed, and deny the infliction of any material damage.