When flying over land a navigator can determine the drift of his vessel by taking observation on a suitable fixed point on the earth's surface, and adjusting his compass course accordingly. It is probable that a gyroscopic compass will be the standard type for dirigibles. Many aviators have experienced difficulties with the magnetic compass on long flights; although it has served me well always, especially on my transatlantic flight as Captain Alcock's navigator. Over the sea no fixed point is available, so that the motion of the wind must be checked periodically. One method is for the navigator to make astronomical observations, and from them deduce his position on the chart. Another may be the use of bombs which ignite on the water and give out a dense smoke or a bright light, lasting for several minutes. During the day the navigator sights on the smoke, and during the night on the light, and thus discovers the wind's velocity and direction. An invention that could simplify navigation would be some form of ground-speed meter, showing at a glance the rate of progress over the earth (as distinct from air speed), with either a following or a contrary wind. The most valuable means of airship navigation will be that of directional wireless. Communication from two separate stations, which could be either land terminals or stationary ships in the ocean, gives the direction of the transmitted wireless waves and signals to the dirigible its bearings. The position is then laid off on the chart, and the course regulated accordingly. This method was used by the German Zeppelins during the war. Of equal importance to the structural and navigational equipment of airships is the provision of suitable terminals for each route. These would require, among other necessities, an aërodrome of about one mile square; a double airship shed capable of housing two vessels; a mooring-out tower; mechanical gear for transferring an airship from the mooring tower to the shed; hydrogen generating and storage plant; repair workshops and stores; meteorological offices; wireless telegraphy installation; electrical night signaling and landing arrangements; a station on the local railway from the main part of the city; a hotel; a garage; and customs and booking offices. The aërodrome must be a short distance from the city served by the airship service. If possible it should be near a chemical works where hydrogen could be produced as a by-product. The ground would be preferably on a site remote from hills and other topographical features likely to cause air disturbances.