5(U COUNT VON Zeppelin's dikioiple air snii\ 



to the wind. The Lake of Constance is often swept bv violent storms. 

 Several times the housing broke loose from its moorings; but precau- 

 tions have now been taken which will prevent a recurrence of theacci 

 dent. The float has been anchored to a block of cement -t^ tons in 

 weight, sunk at a depth of 72 feet, and held in place by steel hawsers 

 250 feet long, secured to two ship's anchors weighing over 5,000 

 pounds each. If despite these precautionary measures the housing 

 should again break loose, two heavy anchors at the bow of the float 

 can be lowered to prevent the float from being driven ashore. 



The air ship now in the course of erection within this structure is 

 •ilO feet long. The supporting body is a cylinder 81> feet in diameter, 

 the ends being tapered so as to ofler the least possible resistance to 

 the air. The skeleton frame of this cylinder is composed of alumiiuim. 

 Sixteen rings separated from one anotlier 2(5 feet hold the fi'umework 

 together. These rings are not circular. l)ut form a twenty-four-sided 

 polygon: their shape is determined by numerous strong alumimnn 

 wires ladiating from a central circle like the spokes of a bicycle wheel. 

 Horizontal l)aisare used to hold the rings together. The entire frame- 

 work will be surrounded ])\ a netting of ramie-tiber cord, remarkable 

 for its gi'eat toughness and tensiU- strength. Within the framework 

 and on each side of thi' rings a similar netting will be disposed. 



The sixteen rings divide the cylinder into seventeen compartments, 

 as it were, each of which will contain a balloon or gas bag. If one of 

 these seventeen independent balloons be injured, the others will remain 

 intact and will still support the air ship. The principle evidently 

 reseml)les that of the water-tight compartments of a steamship. But 

 the system is far safer than that employed in vessels, for no connecting 

 doors or openings are used. 



The V)alloons are made of a light l)ut tough and impenetrable cotton 

 fabric covered with a gas-tight rubber composition. The alumirmm 

 framework is still further protected by an outer water-tight envelope, 

 which serA'es chiefly to protect the balloons from the direct rays of the 

 sun and from rain. The ramie nt>tting serves the purpose of separat- 

 ing the balloons from one another and from the outer envelope. 



The balloons will have a capacity of 851,150 cubic feet and will })e 

 filled with hydrogen gas kept under pressure in cast-iron cylinders, 

 each of which contains 175 cubic feet. Two thousand cylinders will, 

 therefore, be required. The cylinders will be stored on a float, which 

 will be towed to the housing when the balloons are to be inflated. 

 Since a cubic meter (1.308 cubic j^ards) of gas will raise not more than 

 a kilogram (2.2 pounds), it follows that the entire weight of the air 

 ship, including the car. crew, ballast, and motors, must not exceed 

 200 hundredweight. This maximum weight, however, will not be 

 reached by any means. The load will always be such that should one 

 of the balloons give out the others will always be able to support the 

 air ship. 



