The Albatross, a much used type of German machine, was first made at Johnnisthal, near Berlin (about 200 of these machines were made in 1913). Mercedes motors are fitted, capable of attaining a high speed. In the Rumpler monoplane, another well-known German type, the wings are again in the shape of a dove’s wings, the ends being flexible. ‘The stability of the apparatus,’ writes a well-known authority, ‘is assured both by the shape of the wings and their flexibility. It is at once a combination of the inherent stability type and the depending on the warping of surfaces.’ The Rumpler biplane, as in the case of the Aviatik, is remarkable for the space provided for the pilot and observer. In this case also the fuselage is strongly protected. The upper plane varies from that of the majority of German machines; it is not made to move in the centre. There is a short moveable central plane, attached to the fuselage by four tubes. The other planes are fixed to this central plane. The Rumpler monoplane is shown, together with other German designs, including the Gotha monoplane, in a diagram issued in the early part of the war by the French War Office, bearing the words: _German Aeroplanes. Fire on these machines._ (See page 41.) CHAPTER VII THE ZEPPELIN AND OTHER MODERN AIRSHIPS The keenest interest and curiosity is very naturally felt in the Zeppelin airship. Much has been written concerning its peculiar construction—much that is founded on doubtful evidence, and much that is mainly true. At this point we shall limit ourselves to a brief description of the construction of the Zeppelin, and seek to show in simple terms how the type of airship rises and falls. With the heroic acts the Zeppelins have called forth we shall deal later. Now, imagine a long cage tapering to a rounded point at either end. At intervals are thin walls or partitions of aluminium sheet, dividing the cage lengthwise into a large number of drum-shaped compartments, while every part is stiffened and straightened by crossed bars forming diagonal bracing, tying and holding all together into a structure of remarkable strength. Such is the basis of a Zeppelin airship. The whole of the framework is covered with waterproof fabric, the length of some of the patterns being 492 feet in length and 47½ feet in diameter. Beneath is fixed a light framework, forming a kind of keel, and giving additional stiffness. In some designs a cabin is formed in the keel. The cars, which are not unlike the form of a boat, are hung under the keel, one near either end. Near the front, on either side, two light frames spread out, each of which carries one of the propellers, and another pair of frames are fixed in like manner toward the end. At the after end are a number of fins or planes, the purpose of these being to keep the nose of the ship foremost to the wind, as shown in a previous chapter.