The Parseval envelope is of streamline shape which tapers to a point at the tail, and in this ship was of 300,000 cubic feet capacity. The system of rigging being patented, can only be described in very general terms. The suspensions carrying the car are attached to a large elliptical rigging band which is formed under the central portion of the envelope. To this rigging band are attached the trajectory bands which pass up the sides and over the top of the envelope, sloping away from the centre at the bottom towards the nose and tail at the top. The object of this is to distribute the load fore and aft over the envelope. These bands, particularly at the after end of the ship, follow a curved path, so that they become more nearly vertical as they approach the upper surface of the envelope. This has the effect of bringing the vertical load on the top of the envelope; but a greater portion of the compressive force comes on the lower half, where it helps to resist the bending moment due to the unusually short suspensions. A single rudder plane and the ordinary elevator planes were fitted to the envelope. A roomy open car was provided for this ship, composed of a duralumin framework and covered with duralumin sheeting. Two 170 horse-power Maybach engines were mounted at the after end of the car, which drove two metal-bladed reversible propellers. These propellers were later replaced by standard four-bladed wooden ones and a notable increase of speed was obtained. Two officers and a crew of seven men were carried, together with a wireless installation and armament. This airship, together with No. 3, took part in the great naval review at Spithead, shortly before the commencement of the war, and in addition to the duties performed by her in the autumn of 1914, which are mentioned later, carried out long hours of patrol duty from an east coast station in the summer of 1917. In all respects she must be accounted a most valuable purchase. PARSEVAL AIRSHIPS 5, 6 and 7 Parseval No. 5 was not delivered by Germany owing to the war, so three envelopes and two cars were built by Messrs. Vickers on the design of the original ship. These were delivered somewhat late in the war, and on account of the production of the North Sea airship with its greater speed were not persevered with. The dimensions of the envelopes were somewhat increased, giving a cubic capacity of 325,000 cubic feet. Twin Maybach engines driving swivelling propellers were installed in the car, which was completely covered in, but these ships were slow in comparison with later designs, and were only used for the instruction of officers and men destined for the crews of rigid airships then building.