The double sheds for housing vessels of the size specified, three million, five hundred thousand cubic feet capacity, would have two berths, the minimum dimensions of each of which must be eight hundred and fifty feet long, one hundred and fifty feet wide, and one hundred and fifteen feet high. Their contents should include hydrogen filling mains and gear for slinging the airships from the roof when deflated for overhaul. Special arrangements would be made for rapid replenishment of the ships with gas, fuel, and water ballast. If no industrial supply of hydrogen were provided by a nearby factory, the aërodrome should have a generating plant capable of producing fifty thousand cubic feet of hydrogen per hour. Gasometer storage, with a capacity of about five hundred thousand cubic feet, is also a necessity. The meteorological office would issue weather reports for the guidance of airship navigators, and issue navigating instructions to them by means of the wireless installation. The latter should have a range of at least five thousand miles. Each aërodrome would be provided with suitable electric light signals to indicate the position of the landing ground to incoming ships at night, as well as landing lights to point the way to the mooring tower. Trolleys running on guide rails, with electrically driven gear, could move a dirigible from the tower to the shed with a minimum of man power. A suitable mooring tower constitutes an enormous saving of time and labor. The Vickers Patent Mooring Gear, which has been tested satisfactorily, can be worked by half a dozen men; whereas the old method of rope pulling and dragging needs two to four hundred men for landing an airship of three million, five hundred thousand cubic feet capacity. With existing methods, a rigid airship must be housed in a suitable shed when not in flight. The danger and difficulty of removing the ship from its shed, and returning it safely thereto after a journey, restricts the number of actual flying days in the year to those on which such operations can be performed without risk of damage, although a modern rigid airship may be in the air with efficiency and perfect safety in practically any state of the weather. The Patent Mooring Gear renders the landing independent of the weather, while calling for the attendance of only six men to actuate the various mechanical devices employed. In principle, the gear consists of a tall steel mast, of such a height that when the ship is attached by the nose it rides on an even keel at a height of upwards of one hundred feet. The mast has at the top a platform or deck. The head of the tower is entirely enclosed and contains the necessary apparatus for bringing a vessel to rest. This top portion is designed to rotate, so that a ship, when moored, may always lie directly head to wind.